What is the sintering technique of the diamond cutter?
Diamond cutters need to be sintered during the manufacturing process, so the question is what is the sintering technique of this product?
1. Pressurized heating stage:
When hot-pressing sintering, the powder material to be sintered is first compressed to a certain size, that is, when the hot-pressing sintering is performed, a certain pressure is applied to the powder material, and then the temperature is increased. At this stage, the powder has a certain shape because a certain pressure is applied to the powder in advance. When the temperature rises, the powder begins to expand due to heat, and the pores increase. Microscopically, the edges of the particles expand and expand, and macroscopically, the volume increases. In the actual hot-press production process, we often cross-pressurize and heat up. This is the case for the above hot-press process.
In fact, the powder used in the manufacture of diamond products is often added with a protective agent to prevent oxidation to prevent the metal powder from oxidizing. The volatilization temperature of the protective agent is relatively low. The protective agent has become a gas overflowing powder before the agglomeration begins, and the protective agent gas also forms a protective atmosphere in the mold.
2. Pressurization stage:
The pressure is applied to reduce the space between the powders and increase the density of the nodules.
3. Pressurization and heating stage:
As the distance between the powder particles continued to increase under pressure, the atoms constituting the particles began to diffuse to each other, and the lattice aggregation phenomenon (primary sintering started) occurred. In actual production, this stage and the second stage are inseparable from the pressing and heating operations. The purpose is to reduce the distance between the particles, and the edges of the particles begin to partially melt, preparing for the next hot pressing sintering.
4. Insulation and holding pressure stage:
As the pressure and temperature reached a certain limit, the surface of the powder particles began to melt, and at the same time, the atomic distance almost disappeared. At this time, atom migration and diffusion began, the grain lattice was distorted, and the metal particles infiltrated into each other. The density of the sintered body increased sharply at this stage, reaching about 96-98% of the theoretical density. Due to the diffusion of atoms, molecules and crystal lattices, the crystal lattices of atoms and molecules are aggregated. As a result, the overall density increases, the bending strength increases, and the hardness also increases.
5. Cooling and holding pressure stage:
At this stage, the nodule has been sintered and formed. Maintaining a certain pressure and lowering the temperature can prevent the nodular springback of the nodule from increasing after the hot pressing stops. Diffusion is the key to product quality. The driving force for diffusion comes from the migration of atoms, molecules, and lattices. Factors that affect diffusion are: particle size (raw material), temperature, pressure, and sintering time for hot-press sintering. The three factors of sintering temperature, pressure and sintering time are called the three elements of sintering.
The sintering technique of the diamond cutter head is divided into five stages, namely: pressurizing and heating phase-pressurizing phase-pressurizing, heating up phase-heat preservation and pressure holding phase-cooling and pressure holding phase. Each stage has some requirements for each stage, everyone must pay attention when sintering.