Why vacuum sintered diamond saw blades are recommended

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In powder sintering, the sintering atmosphere is very important to ensure the smooth progress of sintering and the quality of the product. If the protective gas is not passed, both the saw blade tip and the matrix will be oxidized by oxygen in the air, causing the matrix to burn out and the mechanical properties of the tool tip will be compromised. Decrease, such as increased brittleness, reduced strength, etc. Therefore, protective gas is passed from beginning to end during sintering. Industrial sintering atmospheres are mainly hydrogen, dissociated ammonia gas, endothermic or exothermic gases, vacuum, nitrogen, etc., which all have a deoxidizing effect to prevent saw blade oxidation and promote smooth sintering.

Diamond saw blade production process
The current production process of diamond saw blades is roughly as follows: batching-mixing-feeding-cold pressing forming-sintering. Among them, the sintering process mainly uses well-type batch furnaces, reducing atmosphere furnaces, etc. to sinter the diamond matrix.

1. Protective atmosphere sintering process
During the sintering process, a mixed gas of hydrogen and nitrogen decomposed from ammonia is used as a protective atmosphere to sinter the diamond matrix. Both hydrogen and nitrogen have deoxidation effects.
The main disadvantages of the protective atmosphere sintering process are:
(1) If you do not pay attention to the dew point control of the reducing atmosphere, sintering problems may easily occur;
(2) A large amount of gas is consumed during the sintering process, and the production cost is high;
(3) If the gas discharged from the furnace is improperly operated, it is easy to explode, and the safety performance is extremely unreliable;
(4) The quality of the carcass is unstable, and it is easy to cause cutting consumption to be too fast or too blunt.

2. Vacuum sintering process
In view of the shortcomings in protective atmosphere sintering, we use vacuum sintering instead of protective atmosphere sintering for the sintering process of diamond saw blades. The hardness, strength and impact toughness of the diamond matrix can be further improved. Strengthening the holding power of diamonds by the matrix, significantly improving the service life of diamond tools. After many experiments, diamond segments with the same formula, concentration and strength were sintered in a vacuum state and in a protective atmosphere. The experimental results It shows that the impact toughness, flexural strength and hardness of the nodes in the vacuum state are greatly improved compared with the nodes sintered in the protective atmosphere.
Figure 1 is a scanning electron microscope photo of the diamond holding state in the saw blade after sintering and cutting under vacuum. Figure 2 is a scanning electron microscope photo of the diamond holding state in the saw blade after sintering and cutting under protection. Judging from the gap between the matrix and the diamond, the holding state of the diamond in Figure 1 is better than that in Figure 2.

figure 1

figure 2

Vacuum sintered diamond saw blade conclusion:
Through the analysis of the vacuum sintering process of diamond saw blades, the following conclusions are drawn:
Vacuum sintering eliminates the adsorbed water vapor and air in the powder, preventing the metal powder from oxidizing during sintering. There is no incomplete removal of oxides like in a protective atmosphere. At the same time, the degree of vacuum required for vacuum sintering is not high and is easy to achieve in actual production. Moreover, from a cost perspective, sintering under a protective atmosphere consumes much more gas than vacuum sintering. Therefore, vacuum sintering can significantly reduce the cost of diamond tool manufacturing cost.

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