申请人:Minnesota Mining and Manufacturing Company
公开号:US05185299A1
公开(公告)日:1993-02-09
Microcrystalline alpha-alumina based ceramic articles comprising at least 60% alumina by weight, and 0.1-7.0 percent by weight iron equivalence in which substantially all the alumina is in the alpha phase having a uniform grain structure comprising alpha alumina crystallites with an average crystallite size less than 0.5 micrometer and a density greater than 90% theoretical are disclosed. Ceramic articles particularly useful as high modulus refractory fibers, among other shaped bodies such as beads, flakes, coatings, and shaped or randomly-shaped abrasive particles, are produced from a unique sol-gel process wherein hydroxy iron polymers are utilized to nucleate the alpha alumina transformation. An inherent advantage of the unique process disclosed is the resulting fine grained microstructure, and a surface roughness height of less than 100.0 nm, which is essential if a ceramic article such as an alpha alumina fiber is to have reasonable strength.
本发明涉及以微晶α-氧化铝为基础的陶瓷制品,其含有至少60%的氧化铝重量,并含有0.1-7.0%的重量当量铁,其中几乎所有的氧化铝都处于α相中,具有均匀的晶粒结构,包括平均晶粒尺寸小于0.5微米的α-氧化铝晶体和密度大于90%理论值。本发明通过一种独特的溶胶-凝胶过程生产出陶瓷制品,特别是高模量耐火纤维,以及其他形状如珠子、片状、涂层和形状或随机形状的磨料颗粒。该过程利用羟基铁聚合物来促进α-氧化铝的转化,其固有优点是细晶粒的微观结构和表面粗糙度高度小于100.0纳米,这对于像α-氧化铝纤维这样的陶瓷制品具有合理的强度是必要的。