Zirconium oxide composite boron nitride refractory product

Abstract

The invention belongs to the field of a refractory material, and mainly relates to a zirconium oxide composite boron nitride refractory product. A high-purity zirconium oxide refractory material is taken as a main body, a certain ratio of boron nitride is compounded on the work surface within a certain thickness, and a composite layer contains boron nitride, so that the operating temperature of the refractory material can be improved, and the corrosion resistance and the thermal shock resistance are improved; meanwhile, a protective layer can be formed between a hearth and the refractory material, so that cross contamination of the zirconium oxide refractory material and the material inside the hearth is reduced. A backing layer is still made of the high-purity zirconium oxide refractory material, so that the roles of heat preservation, heat insulation and the like are played by using the characteristics that zirconium oxide is heat-resisting, small in heat-conducting coefficient and the like. Zirconium oxide in the composite layer containing boron nitride and zirconium oxide inside the backing layer which does not contain boron nitride are in an overall structure, and are synchronously sintered, zirconium oxide plays a role of a skeleton, and boron nitride in the composite layer is fixed at the periphery of zirconium oxide and tightly connected with the backing layer, so that boron nitride is effectively prevented from being peeled off.

Description

technical field [0001] The invention belongs to the field of refractory materials, and mainly relates to a zirconia composite boron nitride refractory product. Background technique [0002] Zirconia is an important refractory raw material with a melting point as high as 2715°C and excellent physical and chemical properties. In order to improve the performance of many refractories, a certain amount of zirconia is added, such as fused AZS bricks, Al 2 o 3 -ZrO 2 -C brick, Cr 2 o 3 -Al 2 o 3 -ZrO 2 bricks etc. [0003] High-purity zirconia refractory products usually refer to refractory products with a zirconia (including stabilizer) content of more than 98%. It uses zirconia particles or zirconia hollow spheres, zirconia fine powder, stabilizers, binders, etc. as raw materials. Refractory products prepared by casting, pouring, machine pressing, isostatic pressing, ramming and other molding methods. High-purity zirconia refractory has the advantages of high service te...

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Problems solved by technology

Because hexagonal boron nitride also has the problem of being difficult to sinter, pure boron nitride products often need high temperature and high pressure to achieve sintering when sintering, and the coating cannot reach the high pressure condition when it is used. Generally, various "easy-sintering bodies" are added to the coating "Or use ultra-fine powder to achieve sintering. The disadvantage is that adding "easy-sintered body" is easy to introduce impurities, resulting in low operating temperature. For example, the common boron nitride-alumina system boron nitride coating is to add a certain amount to the coating. The ratio of alumina, because alumina can be sintered at 1600°C, the coating can be hardened, but because the high temperature resistance of alumina is lower than that of boron nitride, the use temperature of pure alumina refractories is below 1800°C, which determines The use temperature of this coating will not exceed 2000°C; and the addition of ultra-fine powder will cause a large firing shrinkage ratio, such as pure boron nitride with a particle size of less than 5 microns as the main body and nano boron nitride as the main body. Coating, the advantage of this kind of coating is that in the final boron nitride coating, the content of boron nitride is high, and the temperature resistance is high. The disadvantage is that the coating is dense and the firing shrinkage is large. For example, the firing shrinkage of zirconia sand bricks is Between 0.5% and 1%, and the firing shrinkage of this easy-to-densify coating is more than 3%. If this coating is applied to the surface of zirconia sand bricks, the firing shrinkage of the two materials is very different. It is easy to cause coating cracks or delamination from the applied base material