Diamond segment is a principle of conducting electricity through graphite, under high temperature and high pressure environment, the graphite mould will increase the high temperature of the segment, and finally through the melting of the metal powder in the segment, after various physical and chemical reactions, various alloys hold the diamond powder. Let the diamond segment become a metal block with strong abrasive and strong holding force. So such a block has experienced high temperature, can it still withstand high temperature?
First of all，before the question of whether the diamond segment can withstand high temperatures, it is necessary to understand the high temperature range to be discussed. How high is it to be considered high temperature?
High temperature is relative to low temperature and normal temperature, when people are outdoors in summer, the body temperature exceeds 40 degrees Celsius or even 50 degrees Celsius. At this time, people are experiencing high temperatures.
For diamond segments, high temperature also has this definition. Because the diamond segment is composed of two parts: diamonds and metal powder, when the sintering temperature reaches a certain level, due to the metal is in a high-pressure environment and the pressure and temperature have reached a certain limit, the surface of the metal powder particles begins to melt, at the same time, the atomic distance is infinitely reduced because of the pressure.The infinitely shrinking atoms begin to migrate and diffuse. The specific expression is that the crystal lattice of the metal particles changes, the metal particles penetrate each other, and chemical and physical reactions begin to occur continuously.During the entire sintering process, the metal atoms continue to squeeze and react violently. This squeezing causes the metal to form new blocks, which leads to a sharp increase in density, reaching about 96-98% of the theoretical density. And because the heat preservation and pressure holding process lasts for a long time, the metal and diamond also undergo violent physical and chemical reactions. For example, iron powder or cobalt powder and diamond form a more stable structure, which plays a role in fixing the diamond.
So how much temperature is acceptable for metal sintering? For copper powder, the temperature of about 1050 degrees Celsius is its melting point, If the copper powder is completely melted, there will be leakage of the copper powder. Especially in a high-pressure environment, the copper powder can not be completely melted, so the temperature must be lower than 1050 degrees Celsius. Let’s take a look at the temperature of diamond. The carbonization temperature of diamond is 1050 degrees Celsius.However, studies have found that diamond has a slower oxidation reaction at 850 degrees Celsius. This reaction is also called diamond carbonization, which means that during this process, diamond is gradually turning into carbon, and carbon obviously does not have the ability to cut hard materials. Therefore, in order to avoid excessive oxidation of carbon, the sintering temperature cannot be higher than 850 degrees Celsius.
In fact, during the sintering process of diamond segments, the high temperature of 850 degrees Celsius is rarely used.The commonly used temperature is between 750-850, so that the slowest carbonization speed of the diamond tip can be maintained to the maximum, and the metal can also be maintained to reach a higher sintering temperature. Under such high temperature, the metal powder reacts quickly to form a diamond segments, If you need a harder diamond segments product, you need to use tools such as PCD or PDC. This article will not introduce these two products too much.
So finally back to the question of this article, can the diamond segments withstand high temperatures? As we mentioned above, since the sintering process is completed at a temperature of about 800 degrees Celsius, it is obvious that the highest temperature of the segment will not be higher than 800 degrees Celsius. In fact, our common solder soldering temperature is between 620-800 degrees Celsius. Usually, the segment is kept at a high temperature of 600 degrees Celsius for a long time, and there will be obvious flow of material at the welding point of the segment. Therefore, the processing temperature of the diamond segment should not exceed 600 degrees Celsius.Therefore, in order to avoid this situation, it is necessary to use cooling water to cool the segment in the process of cutting hard stone with the diamond segment.