摘要:
Disclosed herein are plate-like composite ferrite fine particles for magnetic recording comprising plate-like composite ferrite containing Ba fine particles which contain Ti of 2 to 5.0 atomic % based on Fe.sup.3+ and Ni in the range of 1.2.ltoreq.Ni/Ti.ltoreq.4 by molar ratio, which have zinc in the vicinity of the particles surfaces in the form of a solid solution, which have an average particle diameter of 0.01 .mu.m to 0.08 .mu.m, and the coercive force of which scarcely varies with the rise in temperature in the temperature range of -20.degree. C. to 120.degree. C., and a process for producing such plate-like composite ferrite fine particles.
摘要:
The disclosure describes a non-magnetic undercoating layer for a magnetic recording medium, coated on the surface of a non-magnetic substrate comprising:non-magnetic particles selected from the group consisting of particles (1) and (2):(1) coated acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles which are produced by adhering not less than 0.01 to 20 wt % (calculated as Al, SiO.sub.2 or Al and SiO.sub.2, and based on acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material) of an oxide or a hydroxide containing Al, Si or both Al and Si to the surfaces of acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material, and have a molecular weight-dependent parameter .alpha. represented by the following formula of not less than 0.5:As=K.sub.1 .multidot.M.sup..alpha.wherein M represents the number-average molecular weight of a binder resin, As represents the saturation adsorption of said binder resin, and K.sub.1 represents a constant used for measuring As and dependent on the binder resin and a solvent,(2) BaO.4.5Fe.sub.2 O.sub.3 particles having an average particle diameter of not more than 0.1 .mu.m; anda binder resin.
摘要:
The disclosure describes a non-magnetic undercoating layer for a magnetic recording medium, coated on the surface of a non-magnetic substrate comprising: non-magnetic particles selected from the group consisting of particles (1) and (2): (1) coated acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles which are produced by adhering not less than 0.01 to 20 wt % (calculated as Al, SiO.sub.2 or Al and SiO.sub.2, and based on acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material) of an oxide or a hydroxide containing Al, Si or both Al and Si to the surfaces of acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material, and have a molecular weight-dependent parameter .alpha. represented by the following formula of not less than 0.5: As=K.sub.1 .multidot.M.sup..alpha. wherein M represents the number-average molecular weight of a binder resin, As represents the saturation adsorption of said binder resin, and K.sub.1 represents a constant used for measuring As and dependent on the binder resin and a solvent, (2) BaO.multidot.4.5Fe.sub.2 O.sub.3 particles having an average particle diameter of not more than 0.1 .mu.m; and a binder resin.
摘要翻译:本发明描述了一种涂覆在非磁性基材表面上的用于磁记录介质的非磁性底涂层,包括:选自颗粒(1)和(2)的非磁性颗粒:(1)涂覆 通过粘附不小于0.01至20重量%(以Al,SiO 2或Al和SiO 2计算,并以针状或纺锤形α-Fe2O3颗粒为核心材料)制备的针状或纺锤状α-Fe2O3颗粒, 含有Al,Si或Al和Si的氧化物或氢氧化物作为核心材料的针状或纺锤形α-Fe2O3颗粒的表面,并且具有不低于下列公式的分子量依赖参数α 比0.5:As =K1xMα其中M表示粘合剂树脂的数均分子量,As表示所述粘合剂树脂的饱和吸附,K1表示用于测量As的常数,并且取决于粘合剂树脂和溶剂, ( 2)平均粒径不大于0.1μm的BaO x 4.5 Fe 2 O 3粒子; 和粘合剂树脂。
摘要:
Disclosed herein are plate-like composite Ba-containing ferrite fine particles for magnetic recording, containing Ni, Co and Ti in the molar ratios defined by 0.02.ltoreq.Ni/Fe.ltoreq.0.10, 0.01.ltoreq.Co/Fe.ltoreq.0.10 and 0.01.ltoreq.Ti/Fe.ltoreq.0.10, but 0.03.ltoreq.(Ni+Co)/Fe.ltoreq.0.14 and Ti/(Ni+Co)
摘要:
The disclosure describes a non-magnetic undercoating layer for a magnetic recording medium, coated on the surface of a non-magnetic substrate comprising:non-magnetic particles selected from the group consisting of particles (1) and (2):(1) coated acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles which are produced by adhering not less than 0.01 to 20 wt % (calculated as Al, SiO.sub.2 or Al and SiO.sub.2, and based on acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material) of an oxide or a hydroxide containing Al, Si or both Al and Si to the surfaces of acicular or spindle-shaped .alpha.-Fe.sub.2 O.sub.3 particles as a core material, and have a molecular weight-dependent parameter .alpha. represented by the following formula of not less than 0.5:As=K.sub.1 .multidot.M.sup..alpha. wherein M represents the number-average molecular weight of a binder resin, As represents the saturation adsorption of said binder resin, and K.sub.1 represents a constant used for measuring As and dependent on the binder resin and a solvent,(2) BaO.4.5Fe.sub.2 O.sub.3 particles having an average particle diameter of not more than 0.1 .mu.m; anda binder resin.
摘要:
A magnetic recording medium exhibiting a high coercive force and excellent squareness having a substrate, an underlayer formed on the substrate, and a spinel-type iron oxide thin film with maghemite as a main component formed on the underlayer. The spinel-type iron oxide thin film has a thickness (t) of 5 to 50 nm, is constituted by grains having an average grain size (D) of 5 to 30 nm, standard deviation of sizes of grain of not more than 4 nm and a ratio (D/t) of the average grain size (D) to the thickness (t) of less than 1.0, exhibits a coercive force of not less than 159 kA/m (2,000 Oe) and a coercive squareness ratio S* of not less than 0.5:1 in a longitudinal recording medium or a squareness ratio not less than 0.75:1 in a perpendicular recording medium.
摘要翻译:具有高矫顽力和具有基底的优良矩形性的磁记录介质,在基底上形成的底层和在底层上形成有以磁赤铁矿为主要成分的尖晶石型氧化铁薄膜。 尖晶石型氧化铁薄膜的厚度(t)为5〜50nm,由平均粒径(D)为5〜30nm的晶粒构成,粒径不超过4nm的标准偏差 平均粒径(D)与厚度(t)的比(D / t)小于1.0时,矫顽力为159kA / m 2(2000Oe),矫顽截面比S * 在纵向记录介质中不小于0.5:1,或垂直记录介质中不小于0.75:1的矩形比。
摘要:
The silica gel carrying a titanium oxide photocatalyst in a high concentration of the present invention is characterized in that the concentration of the titanium oxide contained in the pores near the surface of the silica gel is 7-70% by weight, said silica gel having an average pore diameter of 6-100 nm, provided that the concentration gradient is provided such that the amount of the titanium oxide contained in the pores near the surface of the silica gel is 1.5 times or more than the amount of the titanium oxide contained in the pores near the central part of the silica gel.
摘要:
Magnetic metal particles containing iron as a main component, comprising cobalt in an amount of usually 20 to 50 atm %, calculated as Co, based on whole Fe, aluminum in an amount of usually 3 to 15 atm %, calculated as Al, based on whole Fe and a rare earth element in an amount of usually 3 to 20 atm %, calculated as rare earth element, based on whole Fe, and having an average major axis diameter of usually 0.02 to 0.065 μm, preferably from 0.02 to less than 0.05 μm, a coercive force of usually 159.2 to 222.9 kA/m (2,000 to 2,800 Oe), a soluble Na content of usually not more than 30 ppm, a soluble Ca content of usually not more than 100 ppm, and an oxidation stability Δσs of usually not more than 10%.
摘要:
A perpendicular magnetic recording medium, comprises a substrate; a soft-magnetic layer formed on the substrate; an NaCl-type oxide layer for orientation control formed on the soft-magnetic layer, having a thickness of from more than 0 to less than 10 nm; and a magnetic recording layer formed on the NaCl-type oxide layer for orientation control, comprising a maghemite thin film. Such a perpendicular magnetic recording medium is capable of showing excellent magnetic properties, a high recording resolution and improved surface properties.
摘要:
Spindle-shaped metal particles and a process for producing magnetic spindle-shaped metal particle containing iron as a main component, which contains cobalt of 8 to 45 atm % calculated as Co, aluminum of 5 to 20 atm %, calculated as Al, and a rare earth element of 1 to 15 atm %, calculated as rare earth element, wherein the particles have an average major axial diameter of 0.05 to 0.15 &mgr;m, an average minor axial diameter of 0.010 to 0.022 &mgr;m, an aspect ratio of 4:1 to 8:1, a particle size distribution of not more than 0.20, and an X-ray crystallite size D110 of 12.0 to 17.0 nm. The spindle-shaped metal particles have a high coercive force, an excellent particle coercive force distribution, a large saturation magnetization and an excellent oxidation stability, and are excellent in a squareness (Br/Bm) of the sheet due to a good dispersibility in a binder resin.