{"id":3857,"date":"2026-06-04T07:10:02","date_gmt":"2026-06-04T07:10:02","guid":{"rendered":"https:\/\/nbaem.com\/?p=3857"},"modified":"2026-05-27T08:28:54","modified_gmt":"2026-05-27T08:28:54","slug":"meaning-of-remanence","status":"publish","type":"post","link":"https:\/\/nbaem.com\/vi\/meaning-of-remanence\/","title":{"rendered":"\u00dd ngh\u0129a c\u1ee7a Remanence Br cho v\u1eadt li\u1ec7u t\u1eeb n\u0103ng"},"content":{"rendered":"<h2>V\u1eadt L\u00fd c\u1ee7a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Remanence\" target=\"_blank\" rel=\"noopener\">\u0110\u1ed9 gi\u1eef t\u1eeb<\/a>: N\u00f3 ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<\/h2>\n<p>B\u1ea1n c\u00f3 t\u1eebng t\u1ef1 h\u1ecfi t\u1ea1i sao m\u1ed9t s\u1ed1 v\u1eadt li\u1ec7u v\u1eabn t\u1eeb t\u00ednh ngay c\u1ea3 khi b\u1ea1n lo\u1ea1i b\u1ecf tr\u01b0\u1eddng t\u1eeb t\u00ednh b\u00ean ngo\u00e0i? S\u1ee9c t\u1eeb c\u00f2n s\u00f3t l\u1ea1i n\u00e0y \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 <strong>t\u1eeb t\u00ednh d\u01b0<\/strong>, v\u00e0 hi\u1ec3u \u00fd ngh\u0129a c\u1ee7a s\u1ef1 d\u01b0 t\u1eeb l\u00e0 kh\u00f3a \u0111\u1ec3 m\u1edf kh\u00f3a c\u00e1ch ho\u1ea1t \u0111\u1ed9ng c\u1ee7a nam ch\u00e2m v\u0129nh vi\u1ec5n. Trong c\u1ed1t l\u00f5i, d\u01b0 t\u1eeb ($B_r$) l\u00e0 th\u01b0\u1edbc \u0111o m\u1eadt \u0111\u1ed9 t\u1eeb th\u00f4ng c\u00f2n l\u1ea1i b\u1ecb kh\u00f3a b\u00ean trong m\u1ed9t v\u1eadt li\u1ec7u sau khi l\u1ef1c t\u1eeb \u0111\u00f3ng vai tr\u00f2 truy\u1ec1n \u0111\u1ed9ng gi\u1ea3m xu\u1ed1ng b\u1eb1ng kh\u00f4ng.<\/p>\n<hr \/>\n<h3>C\u8996nh nh\u00ecn vi m\u00f4<\/h3>\n<p>\u0110\u1ec3 hi\u1ec3u d\u01b0 t\u1eeb, ch\u00fang ta ph\u1ea3i nh\u00ecn v\u00e0o <strong>v\u1eadt li\u1ec7u s\u1eaft t\u1eeb<\/strong> \u1edf quy m\u00f4 vi m\u00f4. B\u00ean trong nh\u1eefng v\u1eadt li\u1ec7u n\u00e0y, c\u00e1c nguy\u00ean t\u1eed kh\u00f4ng ho\u1ea1t \u0111\u1ed9ng m\u1ed9t m\u00ecnh. Ch\u00fang t\u1ee5 l\u1ea1i th\u00e0nh c\u00e1c v\u00f9ng c\u1ee5c b\u1ed9 nh\u1ecf \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 <strong>mi\u1ec1n t\u1eeb<\/strong>.<\/p>\n<ul>\n<li><strong>Tr\u1ea1ng th\u00e1i Kh\u00f4ng t\u1eeb h\u00f3a:<\/strong> Th\u00f4ng th\u01b0\u1eddng, c\u00e1c m\u00f4men t\u1eeb c\u1ee7a c\u00e1c mi\u1ec1n n\u00e0y h\u01b0\u1edbng v\u1ec1 c\u00e1c h\u01b0\u1edbng ng\u1eabu nhi\u00ean, tri\u1ec7t ti\u00eau l\u1eabn nhau. T\u1eeb t\u00ednh r\u00f2ng b\u1eb1ng kh\u00f4ng.<\/li>\n<li><strong>Tr\u1ea1ng th\u00e1i C\u00f3 t\u1eeb h\u00f3a:<\/strong> Khi ch\u00fang ta \u00e1p d\u1ee5ng m\u1ed9t tr\u01b0\u1eddng t\u1eeb b\u00ean ngo\u00e0i m\u1ea1nh, c\u00e1c mi\u1ec1n n\u00e0y d\u1ecbch chuy\u1ec3n, quay v\u00e0 h\u1ee3p nh\u1ea5t.<\/li>\n<li><strong>\u0110\u1ed9 t\u1eeb h\u00f3a b\u00e3o h\u00f2a:<\/strong> Khi tr\u01b0\u1eddng b\u00ean ngo\u00e0i \u0111\u1ea1t \u0111\u1ec9nh, t\u1ea5t c\u1ea3 c\u00e1c mi\u1ec1n n\u1ed9i b\u1ed9 x\u1ebfp h\u00e0ng ho\u00e0n h\u1ea3o v\u1ec1 m\u1ed9t h\u01b0\u1edbng, \u0111\u1ea1t dung l\u01b0\u1ee3ng t\u1eeb t\u00ednh t\u1ed1i \u0111a.<\/li>\n<\/ul>\n<hr \/>\n<h3>C\u01a1 ch\u1ebf \u0111\u1ecbnh h\u01b0\u1edbng<\/h3>\n<p>\u0110i\u1ec1u g\u00ec x\u1ea3y ra khi tr\u01b0\u1eddng b\u00ean ngo\u00e0i b\u1ecb t\u1eaft \u0111i? Trong c\u00e1c v\u1eadt li\u1ec7u chu\u1ea9n, c\u00e1c mi\u1ec1n s\u1ebd b\u1eadt tr\u1edf l\u1ea1i tr\u1ea1ng th\u00e1i ng\u1eabu nhi\u00ean c\u1ee7a ch\u00fang. Nh\u01b0ng trong c\u00e1c v\u1eadt li\u1ec7u t\u1eeb t\u00ednh ch\u1ea5t l\u01b0\u1ee3ng cao, c\u00e2u chuy\u1ec7n s\u1ebd kh\u00e1c. Nh\u1eefng b\u1edd m\u1eb7t mi\u1ec1n b\u1ecb k\u1eb9t b\u1edfi nh\u1eefng sai l\u1ec7ch vi m\u00f4, t\u1ea1p ch\u1ea5t, ho\u1eb7c c\u1ea5u tr\u00fac tinh th\u1ec3 c\u00f3 ch\u1ee7 \u0111\u00edch b\u00ean trong kim lo\u1ea1i. C\u01a1 ch\u1ebf k\u1eb9t n\u00e0y ng\u0103n c\u00e1c mi\u1ec1n quay tr\u1edf l\u1ea1i b\u1ed1 c\u1ee5c h\u1ed7n \u0111\u1ed9n ban \u0111\u1ea7u. Do \u0111\u00f3, m\u1ed9t l\u01b0\u1ee3ng l\u1edbn <strong>h\u01b0\u1edbng t\u1eeb d\u01b0<\/strong> \u1edf l\u1ea1i c\u1ed1 \u0111\u1ecbnh t\u1ea1i ch\u1ed7, mang l\u1ea1i cho v\u1eadt li\u1ec7u s\u1ee9c t\u1eeb v\u0129nh vi\u1ec5n c\u1ee7a n\u00f3.<\/p>\n<hr \/>\n<h3>T\u01b0\u01a1ng t\u00e1c Trao \u0111\u1ed5i<\/h3>\n<p>\u1ede m\u1ee9c nguy\u00ean t\u1eed s\u00e2u nh\u1ea5t, to\u00e0n b\u1ed9 hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y \u0111\u01b0\u1ee3c th\u00fac \u0111\u1ea9y b\u1edfi m\u1ed9t hi\u1ec7u \u1ee9ng c\u01a1 h\u1ecdc l\u01b0\u1ee3ng t\u1eed c\u00f3 t\u00ean <strong>t\u01b0\u01a1ng t\u00e1c trao \u0111\u1ed5i<\/strong>. L\u1ef1c l\u01b0\u1ee3ng n\u00e0y ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t ch\u1ea5t keo vi m\u00f4, bu\u1ed9c c\u00e1c spin electron c\u1ee7a c\u00e1c nguy\u00ean t\u1eed l\u00e1ng gi\u1ec1ng ph\u1ea3i song song v\u1edbi nhau.<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">\u0110\u1eb7c \u0111i\u1ec3m<\/th>\n<th style=\"text-align: left;\">Kh\u00f4ng c\u00f3 T\u01b0\u01a1ng t\u00e1c Trao \u0111\u1ed5i<\/th>\n<th style=\"text-align: left;\">C\u00f3 T\u01b0\u01a1ng t\u00e1c Trao \u0111\u1ed5i (L\u01b0u h\u00e0nh t\u1eeb t\u00ednh)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>S\u1eafp x\u1ebfp Spin Nguy\u00ean t\u1eed<\/strong><\/td>\n<td style=\"text-align: left;\">Ng\u1eabu nhi\u00ean v\u00e0 d\u1ec5 b\u1ecb ph\u00e1 v\u1ee1<\/td>\n<td style=\"text-align: left;\">B\u1ecb kh\u00f3a ch\u1eb7t theo b\u1ed1 tr\u00ed song song<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Ph\u1ea3n \u1ee9ng v\u1edbi tr\u01b0\u1eddng ngo\u00e0i<\/strong><\/td>\n<td style=\"text-align: left;\">\u1ee8ng magnet t\u1ea1m th\u1eddi<\/td>\n<td style=\"text-align: left;\">Ghi nh\u1edb l\u00e2u d\u00e0i (<strong>Kh\u1ea3 n\u0103ng gi\u1eef t\u1eeb<\/strong>)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Thu\u1ed9c t\u00ednh v\u1eadt li\u1ec7u k\u1ebft qu\u1ea3<\/strong><\/td>\n<td style=\"text-align: left;\">Kh\u00f4ng t\u1eeb t\u00ednh ho\u1eb7c t\u1ea1m th\u1eddi<\/td>\n<td style=\"text-align: left;\">Cao <strong>\u0111\u1ed9 t\u1eeb d\u01b0<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Li\u00ean k\u1ebft nguy\u00ean t\u1eed m\u1ea1nh m\u1ebd n\u00e0y ch\u00ednh l\u00e0 c\u00e1ch ch\u00fang t\u00f4i thi\u1ebft k\u1ebf c\u00e1c gi\u1ea3i ph\u00e1p t\u1eeb t\u00ednh hi\u1ec7u su\u1ea5t cao duy tr\u00ec t\u00ednh \u1ed5n \u0111\u1ecbnh tr\u01b0\u1eddng t\u1eeb l\u00e2u d\u00e0i cho th\u1ecb tr\u01b0\u1eddng to\u00e0n c\u1ea7u.<\/p>\n<h2>\u0110\u1ed9 d\u01b0 v\u00e0 v\u00f2ng t\u1eeb: B\u1ea3n thi\u1ebft k\u1ebf tr\u1ef1c quan<\/h2>\n<p>\u0110\u1ec3 th\u1ef1c s\u1ef1 n\u1eafm \u0111\u01b0\u1ee3c \u00fd ngh\u0129a c\u1ee7a \u0111\u1ed9 d\u01b0, ch\u00fang ta ph\u1ea3i xem c\u00e1ch c\u00e1c v\u1eadt li\u1ec7u ferromagnetic ho\u1ea1t \u0111\u1ed9ng d\u01b0\u1edbi tr\u01b0\u1eddng t\u1eeb b\u00ean ngo\u00e0i. H\u00e0nh vi n\u00e0y \u0111\u01b0\u1ee3c l\u1eadp b\u1ea3n \u0111\u1ed3 tr\u00ean m\u1ed9t v\u00f2ng t\u1eeb t\u1eeb, \u0111\u00f3ng vai tr\u00f2 nh\u01b0 b\u1ea3n ph\u00e1c th\u1ea3o tr\u1ef1c quan t\u1ed1i th\u01b0\u1ee3ng \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 hi\u1ec7u su\u1ea5t t\u1eeb t\u00ednh.<\/p>\n<h3>Gi\u1ea3i m\u00e3 \u0111\u01b0\u1eddng cong B-H<\/h3>\n<p>\u0110\u01b0\u1eddng cong B-H ph\u00e1c h\u1ecda m\u1eadt \u0111\u1ed9 t\u1eeb th\u00f4ng ($B$) so v\u1edbi c\u01b0\u1eddng \u0111\u1ed9 tr\u01b0\u1eddng t\u1eeb b\u00ean ngo\u00e0i ($H$). Khi b\u1ea1n \u00e1p d\u1ee5ng m\u1ed9t tr\u01b0\u1eddng ngo\u00e0i l\u00ean v\u1eadt li\u1ec7u \u0111\u00e3 kh\u1eed t\u1eeb, m\u1eadt \u0111\u1ed9 t\u1eeb th\u00f4ng t\u0103ng l\u00ean cho \u0111\u1ebfn \u0111\u1ea1t gi\u1edbi h\u1ea1n \u0111\u01b0\u1ee3c bi\u1ebft \u0111\u1ebfn l\u00e0 t\u1eeb h\u00f3a b\u00e3o h\u00f2a. \u1ede \u0111\u1ec9nh n\u00e0y, to\u00e0n b\u1ed9 c\u00e1c mi\u1ec1n t\u1eeb n\u1ed9i t\u1ea1i \u0111\u01b0\u1ee3c c\u0103n ch\u1ec9nh ho\u00e0n to\u00e0n.<\/p>\n<h3>X\u00e1c \u0111\u1ecbnh \u0111\u1ed9 d\u01b0 ($B_r$)<\/h3>\n<p>Khi b\u1ea1n lo\u1ea1i b\u1ecf tr\u01b0\u1eddng t\u1eeb ngo\u00e0i \u0111\u00f3 ($H = 0$), v\u1eadt li\u1ec7u kh\u00f4ng tr\u1edf v\u1ec1 tr\u1ea1ng th\u00e1i kh\u00f4ng t\u1eeb. M\u1eadt \u0111\u1ed9 t\u1eeb th\u00f4ng c\u00f2n l\u1ea1i b\u1ecb m\u1eafc l\u1ea1i b\u00ean trong v\u1eadt li\u1ec7u l\u00e0 <strong>h\u01b0\u1edbng t\u1eeb d\u01b0<\/strong>, \u0111\u01b0\u1ee3c bi\u1ec3u di\u1ec5n tr\u00ean \u0111\u1ed3 th\u1ecb nh\u01b0 $B_r$. Gi\u00e1 tr\u1ecb c\u1ee5 th\u1ec3 n\u00e0y cho bi\u1ebft ch\u00ednh x\u00e1c m\u1ee9c t\u1eeb d\u01b0 m\u00e0 v\u1eadt li\u1ec7u c\u00f3 th\u1ec3 duy tr\u00ec t\u1ef1 n\u00f3, \u0111\u00e2y l\u00e0 ch\u1ec9 s\u1ed1 then ch\u1ed1t khi ch\u00fang ta thi\u1ebft k\u1ebf c\u00e1c gi\u1ea3i ph\u00e1p hi\u1ec7u qu\u1ea3 cao <a href=\"https:\/\/nbaem.com\/vi\/permanent-magnet-generators\/\">m\u00e1y ph\u00e1t nam ch\u00e2m v\u0129nh c\u1eedu<\/a>.<\/p>\n<h3>M\u1ed1i quan h\u1ec7 gi\u1eefa t\u1eeb d\u01b0 v\u00e0 kh\u00e1ng t\u1eeb ($H_c$)<\/h3>\n<p>Trong khi t\u1eeb d\u01b0 ($B_r$) \u0111o m\u1ee9c t\u1eeb m\u1ea1nh c\u00f2n l\u1ea1i, kh\u00e1ng t\u1eeb ($H_c$) \u0111o kh\u1ea3 n\u0103ng v\u1eadt li\u1ec7u ch\u1ed1ng demagnetization. N\u1ebfu b\u1ea1n mu\u1ed1n bu\u1ed9c t\u1eeb d\u01b0 tr\u1edf v\u1ec1 b\u1eb1ng 0, b\u1ea1n ph\u1ea3i \u00e1p d\u1ee5ng m\u1ed9t tr\u01b0\u1eddng t\u1eeb \u0111\u1ed1i l\u1eadp. \u0110\u1ed9 m\u1ea1nh c\u1ee7a tr\u01b0\u1eddng \u0111\u1ed1i l\u1eadp n\u00e0y l\u00e0 kh\u00e1ng t\u1eeb.<\/p>\n<ul>\n<li><strong>N Remanence cao + S\u1ef1 c\u01b0\u1ee1ng ch\u1ebf cao:<\/strong> D\u1eabn \u0111\u1ebfn m\u1ed9t nam ch\u00e2m permanent m\u1ea1nh m\u1ebd, ch\u1ecbu \u0111\u01b0\u1ee3c s\u1ef1 x\u00e1o tr\u1ed9n t\u1eeb b\u00ean ngo\u00e0i.<\/li>\n<li><strong>N Remanence cao + S\u1ef1 c\u01b0\u1ee1ng ch\u1ebf th\u1ea5p:<\/strong> D\u1eabn \u0111\u1ebfn m\u1ed9t v\u1eadt li\u1ec7u nam ch\u00e2m h\u00f3a d\u1ec5 d\u00e0ng nh\u01b0ng c\u0169ng m\u1ea5t t\u1eeb t\u1eeb nhanh, ph\u00f9 h\u1ee3p cho l\u00f5i t\u1eeb t\u1ea1m th\u1eddi.<\/li>\n<\/ul>\n<h3>S\u1ea3n ph\u1ea9m N\u0103ng l\u01b0\u1ee3ng t\u1ed1i \u0111a ($(BH)_{max}$)<\/h3>\n<p>B\u1eb1ng c\u00e1ch nh\u00ecn v\u00e0o \u0111\u01b0\u1eddng cong kh\u1eed t\u1eeb \u1edf g\u00f3c th\u1ee9 hai c\u1ee7a v\u00f2ng qu\u00e1n t\u1eeb, ch\u00fang ta t\u00ednh to\u00e1n s\u1ea3n ph\u1ea9m n\u0103ng l\u01b0\u1ee3ng t\u1ed1i \u0111a, hay $(BH)<em>{max}$. Gi\u00e1 tr\u1ecb n\u00e0y \u0111\u1ea1i di\u1ec7n cho m\u1eadt \u0111\u1ed9 n\u0103ng l\u01b0\u1ee3ng t\u1eeb tr\u01b0\u1eddng t\u1ed5ng h\u1ee3p \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef b\u00ean trong nam ch\u00e2m. $(BH) c\u00e0ng cao<\/em>{max}$ c\u00f3 ngh\u0129a l\u00e0 v\u1eadt li\u1ec7u c\u00f3 th\u1ec3 mang l\u1ea1i m\u1ed9t c\u00fa \u0111\u00e1nh t\u1eeb m\u1ea1nh m\u1ebd t\u1eeb m\u1ed9t k\u00edch th\u01b0\u1edbc r\u1ea5t nh\u1ecf g\u1ecdn.<\/p>\n<h2>Nam ch\u00e2m c\u1ee9ng so v\u1edbi v\u1eadt li\u1ec7u t\u1eeb m\u1ec1m: Hai m\u1eb7t c\u1ee7a \u0111\u1ed3ng ti\u1ec1n Remanence<\/h2>\n<p>Khi ch\u00fang ta nh\u00ecn v\u00e0o \u00fd ngh\u0129a c\u1ee7a remanence trong c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf, v\u1eadt li\u1ec7u ferromagnetic th\u01b0\u1eddng chia th\u00e0nh hai nh\u00f3m ri\u00eang bi\u1ec7t: c\u1ee9ng v\u00e0 m\u1ec1m. C\u00e1ch m\u1ed9t v\u1eadt li\u1ec7u gi\u1eef l\u1ea1i t\u1eeb t\u00ednh c\u1ee7a n\u00f3 <strong>t\u1eeb t\u00ednh d\u01b0<\/strong> quy\u1ebft \u0111\u1ecbnh ch\u00ednh x\u00e1c n\u01a1i v\u00e0 c\u00e1ch n\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong ng\u00e0nh c\u00f4ng nghi\u1ec7p hi\u1ec7n \u0111\u1ea1i.<\/p>\n<h3>N Remanence \/ N Coercivity cao (Nam ch\u00e2m c\u1ee9ng)<\/h3>\n<p>Nam ch\u00e2m v\u0129nh vi\u1ec5n, ho\u1eb7c v\u1eadt li\u1ec7u t\u1eeb c\u1ee9ng, \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 gi\u1eef m\u1ed9t l\u01b0\u1ee3ng t\u1eeb tr\u01b0\u1eddng c\u00f2n l\u1ea1i l\u1edbn <strong>($B_r$)<\/strong> v\u00e0 ch\u1ed1ng demagnetization. H\u1ecd t\u1ef1 h\u00e0o c\u00f3 c\u1ea3 \u0111\u1ed9 d\u01b0 l\u1edbn v\u00e0 \u0111\u1ed9 c\u1ee9ng cao <strong>, ngh\u0129a l\u00e0 m\u1ed9t khi \u0111\u01b0\u1ee3c magnetize \u0111\u1ea1t \u0111\u1ebfn b\u00e3o h\u00f2a, ch\u00fang v\u1eabn gi\u1eef t\u1eeb t\u00ednh.<\/strong>C\u00e1c v\u1eadt li\u1ec7u n\u00e0y kh\u00f3a c\u00e1c mi\u1ec1n t\u1eeb c\u1ee7a ch\u00fang ch\u1eb7t ch\u1ebd v\u00e0o v\u1ecb tr\u00ed. \u0110i\u1ec1u n\u00e0y khi\u1ebfn ch\u00fang l\u00fd t\u01b0\u1edfng cho c\u00e1c \u1ee9ng d\u1ee5ng y\u00eau c\u1ea7u tr\u01b0\u1eddng t\u1eeb \u1ed5n \u0111\u1ecbnh, l\u00e2u d\u00e0i m\u00e0 kh\u00f4ng c\u1ea7n ngu\u1ed3n \u0111i\u1ec7n li\u00ean t\u1ee5c. N\u1ebfu b\u1ea1n s\u1ea3n xu\u1ea5t \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n ho\u1eb7c m\u00e1y ph\u00e1t, ngu\u1ed3n cung c\u1ea5p premium<\/p>\n<p>These materials lock their magnetic domains tightly in place. This makes them ideal for applications requiring a dependable, long-lasting magnetic field without continuous power. If you are manufacturing electric motors or generators, sourcing premium <a href=\"https:\/\/nbaem.com\/vi\/products\/neodymium-magnet\/\">nam ch\u00e2m neodymium (NdFeB)<\/a> \u0111\u1ea3m b\u1ea3o s\u1ea3n ph\u1ea9m c\u1ee7a b\u1ea1n \u0111\u1ea1t \u0111\u01b0\u1ee3c m\u00f4-men xo\u1eafn \u0111\u1ec9nh v\u00e0 hi\u1ec7u su\u1ea5t trong th\u1eddi gian d\u00e0i b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng v\u1eadt li\u1ec7u c\u00f3 kh\u1ea3 n\u0103ng duy tr\u00ec, \u0111\u1ec3 hi\u1ec3u \u0111\u00fang c\u00e1ch c\u00e1c v\u1eadt li\u1ec7u n\u00e0y ch\u1ecbu \u0111\u01b0\u1ee3c qua nhi\u1ec1u n\u0103m v\u1eadn h\u00e0nh, h\u1eefu \u00edch khi xem x\u00e9t <a href=\"https:\/\/nbaem.com\/vi\/how-long-do-magnets-last\/\">bao l\u00e2u nam ch\u00e2m t\u1ed3n t\u1ea1i<\/a> d\u01b0\u1edbi c\u00e1c \u0111i\u1ec1u ki\u1ec7n m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau.<\/p>\n<h3>Nam ch\u00e2m m\u1ec1m L\u00f5ng t\u1eeb \/ \u0110\u1ed9 t\u1eeb tr\u1edf th\u1ea5p (Nam ch\u00e2m m\u1ec1m)<\/h3>\n<p>\u1ede m\u1eb7t ng\u01b0\u1ee3c l\u1ea1i, c\u00e1c v\u1eadt li\u1ec7u t\u1eeb m\u1ec1m \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 d\u1ec5 b\u1ecb t\u1eeb h\u00f3a v\u00e0 kh\u1eed t\u1eeb. Ch\u00fang th\u1ec3 hi\u1ec7n \u0111\u1ed9 t\u1eeb d\u01b0 th\u1ea5p v\u00e0 \u0111\u1ed9 kh\u00e1ng t\u1eeb th\u1ea5p. Khi tr\u01b0\u1eddng t\u1eeb b\u00ean ngo\u00e0i b\u1ecb b\u1ecf \u0111i, ch\u00fang nhanh ch\u00f3ng tr\u1edf l\u1ea1i v\u1ec1 g\u1ea7n b\u1eb1ng kh\u00f4ng. <strong>gi\u00e1 tr\u1ecb m\u1eadt \u0111\u1ed9 flux t\u1eeb<\/strong> xu\u1ed1ng tr\u1edf l\u1ea1i g\u1ea7n zero g\u1ea7n nh\u01b0 ngay l\u1eadp t\u1ee9c.<\/p>\n<ul>\n<li><strong>\u0110\u1eb7c t\u00ednh l\u00f5i:<\/strong> \u0110\u1ed9 t\u1eeb th\u1ea9m th\u1ea5u cao, v\u00f2ng l\u00f9i t\u1eeb h\u1eb9p v\u00e0 t\u1ed5n th\u1ea5t l\u00f5i t\u1eeb t\u1ed1i thi\u1ec3u.<\/li>\n<li><strong>\u1ee8ng d\u1ee5ng ch\u00ednh:<\/strong> L\u00f5i bi\u1ebfn th\u1ebf, cu\u1ed9n c\u1ea3m v\u00e0 \u0111\u1ed9ng c\u01a1 xe \u0111i\u1ec7n n\u01a1i tr\u01b0\u1eddng t\u1eeb ph\u1ea3i \u0111\u1ed5i chi\u1ec1u h\u00e0ng ngh\u00ecn l\u1ea7n m\u1ed7i gi\u00e2y.<\/li>\n<li><strong>M\u1ee5c ti\u00eau:<\/strong> Gi\u1ea3m t\u1ed1i thi\u1ec3u t\u1eeb d\u01b0 \u0111\u1ec3 ng\u0103n ch\u1eb7n t\u1ed5n th\u1ea5t n\u0103ng l\u01b0\u1ee3ng \u1edf d\u1ea1ng nhi\u1ec7t khi l\u1eb7p t\u1eeb nhanh.<\/li>\n<\/ul>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">Thu\u1ed9c t\u00ednh<\/th>\n<th style=\"text-align: left;\">V\u1eadt li\u1ec7u t\u1eeb c\u1ee9ng (Nam ch\u00e2m v\u0129nh c\u1eedu)<\/th>\n<th style=\"text-align: left;\">V\u1eadt li\u1ec7u t\u1eeb m\u1ec1m (Nam ch\u00e2m t\u1ea1m th\u1eddi)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>Ghi nh\u1edb ($B_r$)<\/strong><\/td>\n<td style=\"text-align: left;\">Cao (gi\u1eef t\u1eeb t\u00ednh d\u1ef1 tr\u1eef m\u1ea1nh)<\/td>\n<td style=\"text-align: left;\">Th\u1ea5p (m\u1ea5t t\u1eeb t\u1eeb t\u00ednh nhanh)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u1ee8ng su\u1ea5t t\u1eeb (Coercivity) ($H_c$)<\/strong><\/td>\n<td style=\"text-align: left;\">Cao (Ch\u1ed1ng m\u1ea5t t\u1eeb)<\/td>\n<td style=\"text-align: left;\">Th\u1ea5p (D\u1ec5 b\u1ecb m\u1ea5t t\u1eeb t\u00ednh)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>L\u01b0u v\u1ef1c qu\u1ea7ng t\u1eeb tr\u01b0\u1eddng<\/strong><\/td>\n<td style=\"text-align: left;\">R\u1ed9ng (S\u1ea3n ph\u1ea9m n\u0103ng l\u01b0\u1ee3ng cao)<\/td>\n<td style=\"text-align: left;\">H\u1eb9p (t\u1ed5n th\u1ea5t n\u0103ng l\u01b0\u1ee3ng th\u1ea5p)<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u1ee8ng d\u1ee5ng \u0111i\u1ec3n h\u00ecnh<\/strong><\/td>\n<td style=\"text-align: left;\">\u0110\u1ed9ng c\u01a1 xe \u0111i\u1ec7n, loa, c\u1ea3m bi\u1ebfn<\/td>\n<td style=\"text-align: left;\">M\u00e1y bi\u1ebfn \u00e1p, l\u00f5i t\u1eeb, relay<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>\u0110o t\u1eeb th\u00f4ng c\u00f2n l\u1ea1i: \u0110\u01a1n v\u1ecb, C\u00f4ng c\u1ee5 v\u00e0 Ti\u00eau chu\u1ea9n<\/h2>\n<p>\u0110o l\u01b0\u1eddng <strong>t\u1eeb t\u00ednh d\u01b0<\/strong> \u0111\u1ea3m b\u1ea3o ch\u00ednh x\u00e1c r\u1eb1ng c\u00e1c th\u00e0nh ph\u1ea7n t\u1eeb t\u00ednh ho\u1ea1t \u0111\u1ed9ng \u0111\u00fang nh\u01b0 mong \u0111\u1ee3i trong c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf. Ch\u00fang t\u00f4i s\u1eed d\u1ee5ng c\u00e1c chu\u1ea9n \u0111o l\u01b0\u1eddng \u0111\u01b0\u1ee3c chu\u1ea9n h\u00f3a v\u00e0 thi\u1ebft b\u1ecb chuy\u00ean d\u1ee5ng \u0111\u1ec3 \u0111\u1ecbnh l\u01b0\u1ee3ng ch\u00ednh x\u00e1c c\u00e1c \u0111\u1eb7c t\u00ednh n\u00e0y.<\/p>\n<h3>\u0110\u01a1n v\u1ecb \u0111o l\u01b0\u1eddng<\/h3>\n<p>Nam ch\u00e2m c\u00f2n l\u1ea1i ($B_r$) \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng hai \u0111\u01a1n v\u1ecb \u0111o ch\u00ednh t\u00f9y theo h\u1ec7 \u0111\u01a1n v\u1ecb ti\u00eau chu\u1ea9n \u0111ang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng:<\/p>\n<ul>\n<li><strong>Tesla (T):<\/strong> \u0110\u01a1n v\u1ecb c\u1ee7a H\u1ec7 th\u1ed1ng Qu\u1ed1c t\u1ebf (SI) <strong>gi\u00e1 tr\u1ecb m\u1eadt \u0111\u1ed9 flux t\u1eeb<\/strong>.<\/li>\n<li><strong>Gauss (G):<\/strong> \u0110\u01a1n v\u1ecb CGS, trong \u0111\u00f3 $1 \\text{ Tesla} = 10,000 \\text{ Gauss}$.<\/li>\n<\/ul>\n<h3>Thi\u1ebft b\u1ecb th\u1eed nghi\u1ec7m<\/h3>\n<p>\u0110\u1ec3 l\u1eadp b\u1ea3n \u0111\u1ed3 <strong>v\u00f2ng l\u01b0\u1ee1ng c\u1ef1c<\/strong> v\u00e0 t\u00ecm gi\u00e1 tr\u1ecb nam ch\u00e2m c\u00f2n l\u1ea1i ch\u00ednh x\u00e1c, c\u1ea7n c\u00e1c d\u1ee5ng c\u1ee5 c\u00f4ng nghi\u1ec7p chuy\u00ean d\u1ee5ng:<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">Thi\u1ebft b\u1ecb<\/th>\n<th style=\"text-align: left;\">Ch\u1ee9c n\u0103ng ch\u1ee7 \u0111\u1ea1o<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>Hysteresisgraph (Permeameter)<\/strong><\/td>\n<td style=\"text-align: left;\">V\u1ebd \u0111\u1ed3 th\u1ecb \u0111\u1ea7y \u0111\u1ee7 <strong>\u0111\u01b0\u1eddng cong m\u1ea5t t\u1eeb<\/strong> \u0111\u1ec3 \u0111o $B_r$ v\u00e0 <strong>, ngh\u0129a l\u00e0 m\u1ed9t khi \u0111\u01b0\u1ee3c magnetize \u0111\u1ea1t \u0111\u1ebfn b\u00e3o h\u00f2a, ch\u00fang v\u1eabn gi\u1eef t\u1eeb t\u00ednh.<\/strong>.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Gaussmeter \/ Teslameter<\/strong><\/td>\n<td style=\"text-align: left;\">S\u1eed d\u1ee5ng m\u1ed9t c\u1ea3m bi\u1ebfn Hall \u0111\u1ec3 \u0111o t\u1eeb tr\u01b0\u1eddng b\u1ec1 m\u1eb7t c\u1ee7a m\u1ed9t chi ph\u1ea7n t\u1eeb tr\u01b0\u1eddng.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Thi\u1ebft b\u1ecb \u0111o flux<\/strong><\/td>\n<td style=\"text-align: left;\">K\u1ebft n\u1ed1i v\u1edbi m\u1ed9t cu\u1ed9n Helmholtz \u0111\u1ec3 \u0111o t\u1eeb th\u00f4ng t\u1ed5ng h\u1ee3p c\u1ee7a <strong>nam ch\u00e2m v\u0129nh c\u1eedu<\/strong>.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>C\u00e1c b\u00e0i \u0111\u00e1nh gi\u00e1 th\u1ef1c t\u1ebf<\/h3>\n<p>Kh\u00e1c bi\u1ec7t <strong>v\u1eadt li\u1ec7u s\u1eaft t\u1eeb<\/strong> th\u1ec3 hi\u1ec7n kh\u1ea3 n\u0103ng gi\u1eef t\u1eeb m\u1ea1nh kh\u00e1c nhau \u0111\u00e1ng k\u1ec3 d\u1ef1a tr\u00ean th\u00e0nh ph\u1ea7n h\u00f3a h\u1ecdc v\u00e0 ch\u1ea5t l\u01b0\u1ee3ng s\u1ea3n xu\u1ea5t c\u1ee7a ch\u00fang.<\/p>\n<ul>\n<li><strong>Nam ch\u00e2m Neodymium (NdFeB):<\/strong> Hi\u1ec7u su\u1ea5t v\u01b0\u1ee3t tr\u1ed9i, th\u01b0\u1eddng duy tr\u00ec \u0111\u1ed9 t\u1eeb d\u01b0 \u1edf m\u1ee9c cao gi\u1eefa <strong>1.0 \u0111\u1ebfn 1.4 Tesla (10.000 \u0111\u1ebfn 14.000 Gauss)<\/strong>.<\/li>\n<li><strong>Nam ch\u00e2m Alnico:<\/strong> T\u1eeb d\u01b0 cao l\u00ean t\u1edbi <strong>1.2 Tesla<\/strong>, nh\u01b0ng d\u1ec5 b\u1ecb kh\u1eed t\u1eeb do h\u1ec7 s\u1ed1 t\u1eeb tr\u1edf th\u1ea5p.<\/li>\n<li><strong>Nam ch\u00e2m Ferro (G\u1ed1m):<\/strong> T\u1eeb d\u01b0 th\u1ea5p, th\u01b0\u1eddng quanh <strong>0.35 Tesla (3.500 Gauss)<\/strong>.<\/li>\n<li><strong>V\u1eadt li\u1ec7u t\u1eeb m\u1ec1m:<\/strong> L\u00f5i t\u1eeb l\u00e0m b\u1eb1ng th\u00e9p silicon \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u1ed9t <strong>l\u00f5i t\u1eeb<\/strong> gi\u1ea3m xu\u1ed1ng g\u1ea7n b\u1eb1ng 0 t\u1eeb t\u00ednh c\u00f2n l\u1ea1i \u0111\u1ec3 t\u1ed1i \u01b0u h\u00f3a s\u1ef1 ti\u00eau hao n\u0103ng l\u01b0\u1ee3ng.<\/li>\n<\/ul>\n<h2>C\u00e1c y\u1ebfu t\u1ed1 c\u00f3 th\u1ec3 l\u00e0m suy gi\u1ea3m ho\u1eb7c ph\u00e1 h\u1ee7y t\u1eeb t\u00ednh c\u00f2n l\u1ea1i<\/h2>\n<p>Khi ch\u00fang ta s\u1ea3n xu\u1ea5t nam ch\u00e2m v\u0129nh c\u1eedu, \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111\u1ed9 t\u1eeb t\u00ednh cao <strong>t\u1eeb t\u00ednh d\u01b0<\/strong> ch\u1ec9 l\u00e0 m\u1ed9t ph\u1ea7n c\u1ee7a cu\u1ed9c chi\u1ebfn. Duy tr\u00ec s\u1ef1 \u1ed5n \u0111\u1ecbnh \u0111\u00f3 m\u1edbi \u0111\u1ea3m b\u1ea3o hi\u1ec7u su\u1ea5t l\u00e2u d\u00e0i. Ngay c\u1ea3 c\u00e1c v\u1eadt li\u1ec7u ferromagnetic m\u1ea1nh nh\u1ea5t c\u0169ng c\u00f3 th\u1ec3 m\u1ea5t m\u1eadt \u0111\u1ed9 t\u1eeb tr\u01b0\u1eddng n\u1ebfu ch\u1ecbu t\u00e1c \u0111\u1ed9ng c\u1ee7a \u0111i\u1ec1u ki\u1ec7n m\u00f4i tr\u01b0\u1eddng kh\u1eafc nghi\u1ec7t.<\/p>\n<p>\u0110\u00e2y l\u00e0 ba y\u1ebfu t\u1ed1 ch\u00ednh c\u00f3 th\u1ec3 l\u00e0m suy gi\u1ea3m ho\u1eb7c ph\u00e1 h\u1ee7y ho\u00e0n to\u00e0n <strong>\u0111\u1ed9 t\u1eeb d\u01b0<\/strong> c\u1ee7a c\u00e1c th\u00e0nh ph\u1ea7n t\u1eeb t\u00ednh c\u1ee7a b\u1ea1n.<\/p>\n<hr \/>\n<h3>Xo\u00e1 t\u1eeb t\u1eeb t\u1eeb t\u00ednh nhi\u1ec7t &amp; Nhi\u1ec7t \u0111\u1ed9 Curie<\/h3>\n<p>Nhi\u1ec7t l\u00e0 k\u1ebb th\u00f9 ph\u1ed5 bi\u1ebfn nh\u1ea5t c\u1ee7a <strong>($B_r$)<\/strong>. Khi nhi\u1ec7t \u0111\u1ed9 t\u0103ng l\u00ean, s\u1ef1 n\u00e1o \u0111\u1ed9ng nhi\u1ec7t trong v\u1eadt li\u1ec7u t\u0103ng l\u00ean, l\u00e0m m\u1ea5t s\u1ef1 c\u0103n ch\u1ec9nh c\u1ee7a c\u00e1c v\u00f9ng t\u1eeb t\u00ednh.<\/p>\n<ul>\n<li><strong>Gi\u1edbi h\u1ea1n nhi\u1ec7t \u0111\u1ed9 v\u1eadn h\u00e0nh:<\/strong> Ngay c\u1ea3 tr\u01b0\u1edbc khi nam ch\u00e2m ho\u00e0n to\u00e0n m\u1ea5t t\u1eeb, nhi\u1ec7t \u0111\u1ed9 t\u0103ng cao c\u00f3 th\u1ec3 g\u00e2y gi\u1ea3m c\u00f3 th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c ho\u1eb7c m\u1ea5t t\u1eeb c\u00f3 th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c trong <strong>\u0111\u1ed9 t\u1eeb d\u01b0<\/strong>.<\/li>\n<li><strong>Nhi\u1ec7t \u0111\u1ed9 Curie:<\/strong> \u0110\u00e2y l\u00e0 ng\u01b0\u1ee1ng tr\u1ecdng y\u1ebfu tuy\u1ec7t \u0111\u1ed1i. N\u1ebfu m\u1ed9t v\u1eadt li\u1ec7u \u0111\u1ea1t \u0111\u1ebfn nhi\u1ec7t \u0111\u1ed9 Curie, tr\u1eadt t\u1ef1 t\u1eeb b\u00ean trong b\u1ecb ph\u00e1 h\u1ee7y ho\u00e0n to\u00e0n, bi\u1ebfn nam ch\u00e2m v\u0129nh vi\u1ec5n th\u00e0nh v\u1eadt li\u1ec7u t\u1ea1m th\u1eddi, phi t\u1eeb. V\u00ed d\u1ee5, nam ch\u00e2m Neodymium ti\u00eau chu\u1ea9n (NdFeB) c\u00f3 nhi\u1ec7t \u0111\u1ed9 Curie th\u1ea5p h\u01a1n nhi\u1ec1u so v\u1edbi Samarium Cobalt (SmCo), khi\u1ebfn k\u1ebf ho\u1ea1ch nhi\u1ec7t trong giai \u0111o\u1ea1n thi\u1ebft k\u1ebf tr\u1edf n\u00ean thi\u1ebft y\u1ebfu.<\/li>\n<\/ul>\n<h3>\u1ee8ng su\u1ea5t C\u01a1 h\u1ecdc<\/h3>\n<p>\u1ea2nh h\u01b0\u1edfng v\u1eadt l\u00fd v\u01b0\u1ee3t ra ngo\u00e0i vi\u1ec7c n\u1ee9t l\u00f5i t\u1eeb; ch\u00fang c\u00f3 th\u1ec3 l\u00e0m bi\u1ebfn \u0111\u1ed5i c\u0103n b\u1ea3n c\u00e1c t\u00ednh ch\u1ea5t t\u1eeb c\u1ee7a n\u00f3. C\u0103ng th\u1eb3ng c\u01a1 h\u1ecdc nghi\u00eam tr\u1ecdng \u2014 nh\u01b0 rung \u0111\u1ed9ng li\u00ean t\u1ee5c, va \u0111\u1eadp m\u1ea1nh, ho\u1eb7c r\u01a1i m\u1ed9t nam ch\u00e2m \u2014 truy\u1ec1n n\u0103ng l\u01b0\u1ee3ng \u0111\u1ed9ng h\u1ecdc v\u00e0o v\u1eadt li\u1ec7u. C\u00fa s\u1ed1c v\u1eadt l\u00fd n\u00e0y l\u00e0m cho c\u00e1c v\u00f9ng t\u1eeb b\u1ecb m\u1eafc k\u1eb9t l\u1ec7ch h\u01b0\u1edbng, d\u1eabn \u0111\u1ebfn s\u1ef1 m\u1ea5t m\u00e1t c\u00f3 th\u1ec3 \u0111o \u0111\u01b0\u1ee3c <strong>t\u1eeb t\u00ednh d\u01b0<\/strong>. \u0110\u1ed1i v\u1edbi c\u00e1c \u1ee9ng d\u1ee5ng c\u00f4ng nghi\u1ec7p c\u00f3 rung \u0111\u1ed9ng cao, vi\u1ec7c l\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u c\u00f3 \u0111\u1ed9 b\u1ec1n c\u1ea5u tr\u00fac \u0111\u1eb7c bi\u1ec7t l\u00e0 v\u00f4 c\u00f9ng quan tr\u1ecdng.<\/p>\n<h3>T\u1eeb tr\u01b0\u1eddng ph\u1ea3n kh\u00e1ng<\/h3>\n<p>Ph\u01a1i nam ch\u00e2m tr\u01b0\u1edbc m\u1ed9t tr\u01b0\u1eddng t\u1eeb ngo\u00e0i \u0111\u1ed1i kh\u00e1ng c\u00f3 th\u1ec3 bu\u1ed9c c\u00e1c v\u00f9ng t\u1eeb \u0111\u1ea3o chi\u1ec1u, t\u1eeb \u0111\u00f3 l\u00e0m gi\u1ea3m t\u1ed5ng th\u1ec3 <strong>\u0111\u1ed9 t\u1eeb d\u01b0<\/strong>.<\/p>\n<ul>\n<li><strong>\u0110\u1ed9 c\u01b0\u1ee1ng t\u1eeb ($H_c$) Kh\u00e1ng:<\/strong> Kh\u1ea3 n\u0103ng ch\u1ecbu \u0111\u1ef1ng c\u1ee7a m\u1ed9t v\u1eadt li\u1ec7u tr\u01b0\u1edbc m\u1ed9t tr\u01b0\u1eddng m\u1ea5t t\u1eeb b\u00ean ngo\u00e0i ho\u00e0n to\u00e0n ph\u1ee5 thu\u1ed9c v\u00e0o \u0111\u1ed9 c\u01b0\u1ee1ng t\u1eeb c\u1ee7a n\u00f3.<\/li>\n<li><strong>\u0110\u01b0\u1eddng cong phi t\u1eeb tr\u01b0\u1eddng:<\/strong> N\u1ebfu t\u1eeb tr\u01b0\u1eddng b\u00ean ngo\u00e0i v\u01b0\u1ee3t qu\u00e1 ng\u01b0\u1ee1ng c\u1ee5 th\u1ec3 c\u1ee7a v\u1eadt li\u1ec7u tr\u00ean <strong>v\u00f2ng l\u01b0\u1ee1ng c\u1ef1c<\/strong>, n\u00f3 \u0111\u1ea9y nam ch\u00e2m v\u01b0\u1ee3t qu\u00e1 gi\u1edbi h\u1ea1n, l\u00e0m c\u1ea1n ki\u1ec7t s\u1ee9c m\u1ea1nh c\u1ee7a n\u00f3 m\u1ed9t c\u00e1ch v\u0129nh vi\u1ec5n.<\/li>\n<\/ul>\n<p>\u0110\u1ec3 \u0111\u1ea3m b\u1ea3o c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u01b0\u1ee3c c\u00e1c bi\u1ebfn \u00e1p v\u1eadn h\u00e0nh n\u00e0y m\u00e0 kh\u00f4ng m\u1ea5t c\u00f4ng su\u1ea5t, \u0111i\u1ec1u thi\u1ebft y\u1ebfu l\u00e0 ph\u1ea3i bi\u1ebft ch\u00ednh x\u00e1c c\u00e1ch \u0111\u00e1nh gi\u00e1 v\u1eadt li\u1ec7u c\u1ee7a b\u1ea1n. B\u1ea1n c\u00f3 th\u1ec3 t\u00ecm hi\u1ec3u th\u00eam v\u1ec1 vi\u1ec7c \u0111\u00e1nh gi\u00e1 c\u00e1c \u0111\u1eb7c t\u00ednh n\u00e0y trong h\u01b0\u1edbng d\u1eabn th\u1ef1c t\u1ebf c\u1ee7a ch\u00fang t\u00f4i v\u1ec1 <a href=\"https:\/\/nbaem.com\/vi\/how-to-measure-magnet-strength\/\">c\u00e1ch \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m<\/a>.<\/p>\n<h2>Ngu\u1ed3n cung c\u1ea5p v\u1eadt li\u1ec7u c\u00f3 d\u01b0 t\u1eeb l\u1edbn: L\u1ee3i th\u1ebf NBAEM<\/h2>\n<p>Khi b\u1ea1n c\u1ea7n nam ch\u00e2m v\u0129nh vi\u1ec5n duy tr\u00ec \u0111\u01b0\u1ee3c s\u1ee9c m\u1ea1nh t\u1eeb t\u00ednh d\u01b0\u1edbi \u00e1p l\u1ef1c, n\u01a1i b\u1ea1n mua v\u1eadt li\u1ec7u c\u00f3 \u00fd ngh\u0129a. T\u1ea1i NBAEM, ch\u00fang t\u00f4i chuy\u00ean cung c\u1ea5p c\u00e1c v\u1eadt li\u1ec7u ferromagnetic ti\u00ean ti\u1ebfn t\u1ed1i \u01b0u <strong>t\u1eeb t\u00ednh d\u01b0<\/strong> cho c\u00e1c \u1ee9ng d\u1ee5ng \u0111\u00f2i h\u1ecfi nh\u1ea5t c\u1ee7a b\u1ea1n. Ch\u00fang t\u00f4i ki\u1ec3m so\u00e1t quy tr\u00ecnh s\u1ea3n xu\u1ea5t t\u1eeb b\u1ed9t th\u00f4 \u0111\u1ebfn s\u1ea3n ph\u1ea9m cu\u1ed1i c\u00f9ng, \u0111\u1ea3m b\u1ea3o c\u00e1c th\u00e0nh ph\u1ea7n c\u1ee7a b\u1ea1n duy tr\u00ec ch\u00ednh x\u00e1c <strong>($B_r$)<\/strong> nh\u1eefng g\u00ec thi\u1ebft k\u1ebf c\u1ee7a b\u1ea1n y\u00eau c\u1ea7u.<\/p>\n<hr \/>\n<h3>\u0110\u1ed3ng kim lo\u1ea1i ti\u00ean ti\u1ebfn<\/h3>\n<p>Ch\u00fang t\u00f4i kh\u00f4ng ch\u1ec9 nung ch\u1ea3y kim lo\u1ea1i; ch\u00fang t\u00f4i thi\u1ebft k\u1ebf c\u1ea5u tr\u00fac nguy\u00ean t\u1eed. C\u00e1c quy tr\u00ecnh luy\u1ec7n kim ti\u00ean ti\u1ebfn c\u1ee7a ch\u00fang t\u00f4i t\u1ed1i \u01b0u ho\u00e1 s\u1ef1 c\u0103n ch\u1ec9nh h\u1ea1t trong <strong>nam ch\u00e2m neodymium (NdFeB)<\/strong> v\u00e0 c\u00e1c h\u1ee3p kim hi\u1ec7u su\u1ea5t cao kh\u00e1c. B\u1eb1ng c\u00e1ch ki\u1ec3m so\u00e1t ch\u00ednh x\u00e1c th\u00e0nh ph\u1ea7n ho\u00e1 h\u1ecdc, ch\u00fang t\u00f4i \u0111\u1ea9y gi\u1edbi h\u1ea1n c\u1ee7a <strong>s\u1ef1 b\u00e3o h\u00f2a t\u1eeb<\/strong>, cho ph\u00e9p v\u1eadt li\u1ec7u c\u1ee7a ch\u00fang t\u00f4i \u0111\u1ea1t \u0111\u1ec9nh cao h\u01a1n v\u00e0 duy tr\u00ec m\u1eadt \u0111\u1ed9 th\u1ef1c l\u01b0u t\u1eeb tr\u01b0\u1eddng v\u01b0\u1ee3t tr\u1ed9i khi tr\u01b0\u1eddng b\u00ean ngo\u00e0i b\u1ecb lo\u1ea1i b\u1ecf.<\/p>\n<h3>K\u1ef9 thu\u1eadt t\u00f9y bi\u1ebfn<\/h3>\n<p>M\u1ecdi \u1ee9ng d\u1ee5ng c\u00f4ng nghi\u1ec7p \u0111\u1ec1u c\u00f3 m\u1ed9t \u0111\u1eb7c tr\u01b0ng ri\u00eang <strong>v\u00f2ng l\u01b0\u1ee1ng c\u1ef1c<\/strong>. D\u00f9 d\u1ef1 \u00e1n c\u1ee7a b\u1ea1n \u0111\u00f2i h\u1ecfi m\u1ee9c \u0111\u1ed9 cao <strong>, ngh\u0129a l\u00e0 m\u1ed9t khi \u0111\u01b0\u1ee3c magnetize \u0111\u1ea1t \u0111\u1ebfn b\u00e3o h\u00f2a, ch\u00fang v\u1eabn gi\u1eef t\u1eeb t\u00ednh.<\/strong> \u0111\u1ec3 ch\u1ed1ng demagnetization ho\u1eb7c c\u00e1c metrics hi\u1ec7u n\u0103ng c\u1ee5 th\u1ec3 \u1edf nhi\u1ec7t \u0111\u1ed9 cao, ch\u00fang t\u00f4i \u0111i\u1ec1u ch\u1ec9nh k\u1ef9 thu\u1eadt c\u1ee7a m\u00ecnh \u0111\u1ec3 ph\u00f9 h\u1ee3p. Ch\u00fang t\u00f4i t\u00f9y ch\u1ec9nh c\u00e1c \u0111\u1eb7c t\u00ednh t\u1eeb t\u00ednh c\u1ee7a c\u00e1c linh ki\u1ec7n c\u1ee7a b\u1ea1n \u0111\u1ec3 c\u00e2n b\u1eb1ng ho\u00e0n h\u1ea3o gi\u1eefa kh\u1ea3 n\u0103ng ghi nh\u1edb v\u00e0 s\u1ef1 \u1ed5n \u0111\u1ecbnh nhi\u1ec7t, \u0111\u1ea3m b\u1ea3o \u0111\u1ed9 tin c\u1eady l\u00e2u d\u00e0i trong th\u1ef1c t\u1ebf. \u0110\u1ec3 \u0111\u1ea3m b\u1ea3o \u0111\u1ed9i ng\u0169 c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 x\u00e1c minh ch\u00ednh x\u00e1c c\u00e1c \u0111\u1eb7c t\u00ednh n\u00e0y trong qu\u00e1 tr\u00ecnh QA, ch\u00fang t\u00f4i c\u0169ng cung c\u1ea5p c\u00e1c insight v\u1ec1 <a href=\"https:\/\/nbaem.com\/vi\/how-to-measure-magnet-strength\/\">c\u00e1ch \u0111o \u0111\u1ed9 m\u1ea1nh c\u1ee7a nam ch\u00e2m<\/a> s\u1eed d\u1ee5ng thi\u1ebft b\u1ecb ki\u1ec3m tra theo chu\u1ea9n c\u00f4ng nghi\u1ec7p.<\/p>\n<h3>Ki\u1ec3m So\u00e1t Ch\u1ea5t L\u01b0\u1ee3ng Kh\u1eaft Khe<\/h3>\n<p>M\u1ed9t l\u00f4 h\u00e0ng y\u1ebfu duy nh\u1ea5t c\u00f3 th\u1ec3 l\u00e0m gi\u00e1n \u0111o\u1ea1n m\u1ed9t chu k\u1ef3 s\u1ea3n xu\u1ea5t to\u00e0n ph\u1ea7n. \u0110\u00f3 l\u00e0 l\u00fd do c\u00e1c quy tr\u00ecnh ki\u1ec3m so\u00e1t ch\u1ea5t l\u01b0\u1ee3ng c\u1ee7a ch\u00fang t\u00f4i gi\u00e1m s\u00e1t m\u1ecdi ch\u1ec9 s\u1ed1 quan tr\u1ecdng tr\u00ean <strong>\u0111\u01b0\u1eddng cong m\u1ea5t t\u1eeb<\/strong>.<\/p>\n<ul>\n<li><strong>Ki\u1ec3m tra lu\u1ed3ng t\u1eeb t\u00ednh:<\/strong> M\u1ecdi l\u00f4 h\u00e0ng \u0111\u1ec1u \u0111\u01b0\u1ee3c ki\u1ec3m tra \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o \u0111\u1ed3ng nh\u1ea5t gi\u1eefa \u0111\u01a1n v\u1ecb Tesla v\u00e0 Gauss.<\/li>\n<li><strong>Ph\u00e2n t\u00edch nhi\u1ec7t:<\/strong> Ch\u00fang t\u00f4i x\u00e1c nh\u1eadn gi\u1edbi h\u1ea1n hi\u1ec7u su\u1ea5t so v\u1edbi <strong>nhi\u1ec7t \u0111\u1ed9 Curie<\/strong> \u0111\u1ec3 ng\u0103n t\u00ecnh tr\u1ea1ng h\u1ecfng h\u00f3c s\u1edbm.<\/li>\n<li><strong>\u0110\u1ed3 th\u1ecb ph\u00e2n c\u1ef1c t\u1eeb t\u00ednh:<\/strong> L\u1eadp b\u1ea3n \u0111\u1ed3 \u0111\u1ea7y \u0111\u1ee7 \u0111\u01b0\u1eddng cong B-H \u0111\u1ea3m b\u1ea3o kh\u00f4ng c\u00f3 t\u1ed5n th\u1ea5t t\u1eeb t\u00ednh l\u00f5i b\u1ea5t ng\u1edd n\u00e0o.<\/li>\n<\/ul>\n<p>B\u1eb1ng c\u00e1ch ch\u1ecdn <a href=\"https:\/\/nbaem.com\/vi\/\">NBAEM<\/a>, b\u1ea1n \u0111ang h\u1ee3p t\u00e1c v\u1edbi m\u1ed9t nh\u00e0 s\u1ea3n xu\u1ea5t cam k\u1ebft v\u1ec1 \u0111\u1ed9 ch\u00ednh x\u00e1c, \u0111\u1ed9 tin c\u1eady v\u00e0 hi\u1ec7u su\u1ea5t t\u1eeb t\u00ednh \u1edf m\u1ee9c \u0111\u1eb3ng c\u1ea5p th\u1ebf gi\u1edbi.<\/p>","protected":false},"excerpt":{"rendered":"<p>\u00dd ngh\u0129a c\u1ee7a remanence \u0111\u01b0\u1ee3c gi\u1ea3i th\u00edch b\u1eb1ng v\u00f2ng hysteresis v\u1edbi \u0111\u01a1n v\u1ecb coercivity Br Tesla Gauss v\u00e0 l\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u cho nam ch\u00e2m NdFeB ferrite v\u00e0 SmCo<\/p>","protected":false},"author":1,"featured_media":1350,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3857","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/nbaem.com\/wp-content\/uploads\/2024\/10\/BH-curve-for-different-material.png","_links":{"self":[{"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/posts\/3857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/comments?post=3857"}],"version-history":[{"count":1,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/posts\/3857\/revisions"}],"predecessor-version":[{"id":3862,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/posts\/3857\/revisions\/3862"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/media\/1350"}],"wp:attachment":[{"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/media?parent=3857"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/categories?post=3857"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nbaem.com\/vi\/wp-json\/wp\/v2\/tags?post=3857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}