Automated Pyrometer Tracking in a Spark Plasma Sintering Apparatus and Method

Abstract

A system and method for compressively sintering a material is described. The method comprises the steps of loading a material to be sintered into a die cavity of a die set and placing the die set into a vacuum chamber of a sintering apparatus, which further comprises a temperature measurement device configured to determine the temperature of material in the die cavity during sintering. The apparatus further comprises a control system configured to move the temperature measurement device during sintering in order to maintain its relative positioning to a target location of the die cavity. The present invention further relates to a sintering apparatus capable of performing this method.

What is claimed is: 
     
         1 . A method of forming a sintered product comprising, in any order, the steps:
 i) loading a material to be sintered into a die cavity of a die set comprising a casing and opposing rams configured to compress the material;   ii) placing the die set into a vacuum chamber of a sintering apparatus, the sintering apparatus comprising a temperature measurement device configured to determine the temperature of material in the die cavity during sintering and a control system configured to move the temperature measurement device during sintering;   iii) positioning the temperature measurement device relative to a target location of the die cavity; and   iv) compressively sintering the material in the die cavity to form the sintered product, wherein, during the compressive sintering, the temperature measurement device is moved in order to maintain the relative positioning to the target location of the die cavity using the control system.   
     
     
         2 . The method of  claim 1 , wherein the method further comprises the step of determining an algorithm relating target location position to temperature, and wherein the control system moves the temperature measurement device based on the algorithm. 
     
     
         3 . The method of  claim 3 , wherein the sintering apparatus further comprises a repositioning device in communication with the temperature measurement device and the control system, and wherein the temperature measurement device is moved by the repositioning device using the control system. 
     
     
         4 . The method of  claim 2 , wherein the step of moving the temperature measurement device comprises determining a position of the die set during compressive sintering. 
     
     
         5 . The method of  claim 4 , wherein the die set comprises an outer casing, an upper ram, and a lower ram, and wherein the step of moving the temperature measurement device comprises determining a position of the upper ram, the lower ram, or both. 
     
     
         6 . The method of  claim 1 , wherein the temperature measurement device is moved continuously during the compressive sintering. 
     
     
         7 . The method of  claim 1 , wherein moving the temperature measurement device is automated. 
     
     
         8 . The method of  claim 1 , wherein the sintering apparatus is a spark plasma sintering apparatus or a direct current sintering apparatus. 
     
     
         9 . The method of  claim 1 , wherein the die cavity is vertically symmetrical. 
     
     
         10 . The method of  claim 9 , wherein the target location of the die cavity is a centerline. 
     
     
         11 . The method of  claim 1 , wherein the temperature measurement device is a pyrometer positioned on the vacuum chamber. 
     
     
         12 . A method of forming a sintered product comprising, in any order, the steps:
 i) loading a material to be sintered into a die cavity of a die set comprising an outer casing and an upper ram and a lower ram configured to compress the material;   ii) placing the die set into a vacuum chamber of a sintering apparatus, the sintering apparatus comprising a pyrometer positioned on the vacuum chamber and configured to determine the temperature of material in the die cavity during sintering and a control system configured to move the pyrometer during sintering;   iii) positioning the pyrometer relative to a centerline of the die cavity; and   iv) compressively sintering the material in the die cavity to form the sintered product, wherein, during the compressive sintering, the pyrometer is moved in order to maintain the relative positioning to the centerline of the die cavity using the control system.   
     
     
         13 . A compressive sintering apparatus comprising
 a) a die set having a die cavity loaded with material to be sintered and comprising a casing and opposing rams configured to compress the material;   b) a vacuum chamber into which the die set is placed   c) a temperature measurement device configured to determine the temperature of material in the die cavity during sintering; and   d) a control system configured to move the temperature measurement device during sintering based on a predetermined algorithm relating position of a target location of the die cavity to temperature.