35results about How to "Reduced linear shrinkage" patented technology

The invention discloses a method for preparing a near-net size of a porous silicon nitride / silicon oxynitride ceramic composite material, which relates to a method for preparing a near-net size of the composite material. The invention solves the problem that the shrinkage rate of the Si3N4 ceramic green body is relatively large during the sintering process. The method is as follows: preparing a porous silicon nitride green body; pre-sintering the green body; impregnating, gelling, drying; and sintering to obtain the porous silicon nitride / silicon oxynitride ceramic composite material. The porous silicon nitride / silicon oxynitride ceramic composite material prepared by the method of the invention can reduce the shrinkage rate of the green body during sintering while meeting the mechanical property requirements. The method of the invention has the advantages of simple process, low cost and good repeatability.

The invention discloses a polyurethane board and a preparation method thereof. The manufacturing method comprises the following steps of uniformly mixing a component A, a component B and compound filler to prepare a foaming material, injecting the foaming material into a die for compression molding, and finally demoulding to form a polyurethane board product, wherein the component A comprises a polyether polyol auxiliary a and a polyester polyol auxiliary b; the component B is isocyanate; the filler is prepared from an inorganic powder material, a plant powder material and a fiber material. According to the manufacturing method, the polyurethane board product is manufactured by uniformly mixing the compound polyester polyol, the isocyanate and the compound filler, injecting the mixture into the die and carrying out heat-preservation pressing. The obtained product is high in mechanical performance strength, low in linear shrinkage rate during storage and use, is not easy to warp after long-term storage and high in production and secondary processing precision, does not easily absorb water and can be applied to the field having high requirement on size precision.

The invention relates to the technical field of building materials, in particular to high coal ash dosage I type inorganic building thermal mortar. The high coal ash dosage I type inorganic building thermal mortar is composed, by mass, of 45-55 parts of P.O 425 cement, 45-55 parts of secondary coal ash, 2.5-3.5 parts of sodium sulfate, 10-15 parts of ash calcium powder, 85-95 parts of glass bead, 0.2-0.4 part of hydroxypropyl methyl cellulose ether, 1-3 parts of VAE redispersible emulsion powder, 0.1-0.3 part of polypropylene fiber and 0.2-0.4 part of rosin air entraining admixture. The high coal ash dosage I type inorganic building thermal mortar has the advantages that the coal ash is used for replacing 45-55 percent of cement, the ash calcium powder and the sodium sulfate are used for exciting the activity of the coal ash, the mechanical property of the thermal mortar is improved, the proper cellulose ether and the redispersible emulsion powder are added to improve the working performance and the bonding performance of the mortar, the cracking resisting performance of the mortar is improved, the dry density and the heat conductivity coefficient of the mortar are lowered, and the heat preservation and insulation performance is improved.