Batch sintering method for high-property silicon nitride ceramic substrate

A batch sintering method for making a high-property silicon nitride ceramic substrate, comprising the following steps:

• (1) stacking silicon nitride ceramic substrate green bodies, putting the silicon nitride ceramic substrate green bodies into a boron nitride crucible, and applying a layer of boron nitride powder between adjacent silicon nitride ceramic substrate green bodies;
• (2) performing step-by-step vacuumization, and then debinding in a nitrogen atmosphere or a reducing atmosphere at 500° C. to 900° C.;
• wherein the step-by-step vacuumization is performed in at least two steps or at least three steps;
• if vacuumization is performed in the at least two steps, parameters of the step-by-step vacuumization include:
• a first step of 20 to 30 minutes of vacuumization for making a vacuum degree reach 20 kPa to 30 kPa, and a second of 10 to 20 minutes of vacuumization for making a vacuum degree less than 10 Pa;
• or if vacuumization is performed in the at least three steps, parameters of the step-by-step vacuumization include:
• a first step of 10 to 15 minutes of vacuumization for making a vacuum degree reach 60 kPa to 80 kPa, a second step of 10 to 15 minutes of vacuumization for making a vacuum degree reach 10 kPa to 30 kPa, and a third step of 10 to 15 minutes of vacuumization for making a vacuum degree less than 10 Pa;
• and then
• (3) performing gas pressure sintering in a nitrogen atmosphere at 1800° C. to 2000° C., thereby completing a batch preparation of the high-property silicon nitride ceramic substrate.