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陶瓷型粘结剂一般使用硅酸乙酯水解液。为了保证有较长的使用期,硅酸乙酯水解液的pH值控制在2左右。加入固化剂的作用,在于提高陶瓷浆料的pH值,使浆料迅速结胶。结胶时间长短直接影响铸件的表面质量,结胶时间过长,会造成浆料中大颗粒粉料沉淀,使表面光洁度降低;结胶时间过短,一方面不利于操作,大铸型有浇不到的危险;另一方面,也降低表面光洁度,例如:用小于200微米的莫来石为骨材,粘结剂用硅酸乙酯水解液,以MgO为硬化剂,结胶时间为1分钟时,型腔表面的Ra为及1.7微米,当结胶时间为10分钟时,Ra为1.1微米
Ceramic binders generally use ethyl silicate hydrolyzate. In order to ensure a longer period of use, ethyl acetate hydrolyzate pH control at 2 or so. The role of adding curing agent, is to raise the pH of the ceramic slurry, the slurry quickly gel. The length of the gel directly affects the surface quality of the castings, and the longer the gel-forming time will result in the precipitation of large-sized particles in the slurry, resulting in a decrease of surface finish. The excessively short gel-forming time is not conducive to operation. Less than the danger; on the other hand, also reduce the surface finish, for example: mullite less than 200 microns as the aggregate, the binder with ethyl silicate hydrolyzate, MgO as a hardener, gel time 1 Min, Ra of the cavity surface was 1.7 μm, Ra was 1.1 μm when the gel time was 10 minutes