摘要:
Titanium dioxide pigments are obtainable by complete hydrolysis of a hydrolyzable titanium compound at from 0 to 100.degree. C. with intensive stirring and with setting of a pH in the range from 3 to 8 and maintenance of this pH within a range of 0.3 units.The titanium dioxide pigments can be employed for the production of cosmetic preparations and medicaments.
摘要:
Catalysts are composed ofa) a magnetizable core,b) which may be coated with a binder andc) which carries catalytically active metals or metal compounds on its surface.
摘要:
A magnetic ink concentrate essentially consisting of a dispersion of superparamagnetic solid particles in water or alcohol in the presence of a dispersant, and a process for its preparation.
摘要:
A magnetorheological fluid essentially consists of magnetic particles which are coated with a polyelectrolyte and are suspended in a polar liquid. The fluid has a magnetorheological effect of more than 100 Pa, measured in a magnetic field of 100 kA/m.
摘要:
.gamma.-Fe.sub.2 O.sub.3 pigments and Fe.sub.3 O.sub.4 pigments with a particle diameter of 2 to 100 nm, a saturation magnetization above 40 nTm.sup.3 /g, a remanence below 10 nTm.sup.3 /g, a Cr content below 40 mg/kg of pigment, a Cu content below 40 mg/kg of pigment and C content below 100 mg/kg of pigment and aqueous suspension of these pigments. The pigments are used in aqueous suspension in the medical sector, in particular as contrast agents in magnetic resonance imaging.
摘要:
A magnetic ink concentrate essentially consisting of a dispersion of superparamagnetic solid particles in water or alcohol in the presence of a dispersant, and a process for its preparation.
摘要:
A finely divided acicular CrO.sub.2 modified with iron, tellurium and/or antimony and having a high coercive force possesses improved heat stability of the residual induction and a relatively narrow distribution of the particle size and of the coercive force. This CrO.sub.2 pigment is obtained by a method in which the iron compound used for the modification is iron oxalate, which is employed in an amount of 1-10% by weight, based on the theoretical CrO.sub.2 yield.
摘要:
A magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic layer applied thereon and containing an acicular chromium dioxide uniformly distributed in a polymeric binder and additives and having a coercive force of at least 60 kA/m, a mean particle length of the chromium dioxide of less than 300 nm, whose factor HD according to the formula ##EQU1## where KT is the coercive force of the magnetic layer in [kA/m], measured in an external field of 380 kA/m, L is the mean particle length and .DELTA.L is the range of the particle size distribution, determined from the numerical distribution of the particle length, both measured in [nm], is greater than 1.85, and a process for the preparation of this chromium dioxide.
摘要:
The invention provides a process for preparing aromatic amines by catalytically hydrogenating the corresponding nitro compounds, especially for preparing tolylenediamine by hydrogenating dinitrotoluene, which comprises using hydrogenation catalysts in which the active component present is a mixture of platinum, nickel and an additional metal on a support.
摘要:
The invention relates to a catalyst for fuel cells which comprises a support, at least one catalytically active metal from the platinum group or an alloy comprising at least one metal of the platinum group and also at least one oxide of at least one metal selected from among Ti, Sn, Si, W, Mo, Zn, Ta, Nb, V, Cr and Zr. The invention further relates to a process for producing such a catalyst and its use.