Domestic diamond powder with more | type of single crystal diamond as raw material, but | type high impurity content, low strength, can only be used in low-end market product demand. A few domestic diamond powder manufacturers use type I1 or Sichuan type single crystal diamond as raw material to produce diamond powder, its processing efficiency is much larger than ordinary diamond powder, which can meet the demand of high-end market. Diamond powder high hardness, good wear resistance, widely used in cutting, grinding, drilling, polishing and other fields. With the development and progress of science and technology, the market demand for diamond powder is getting larger and larger, and the quality requirements are becoming higher and higher. For the diamond powder, the amount of impurities in the diamond powder directly affects the product quality and performance of the powder.
Diszable species
The impurities of diamond powder refers to the non-carbon components in diamond powder, which can be divided into granular external impurities and internal impurities. The external impurities of particles are mainly introduced by raw materials and production process, including silicon, iron, nickel, calcium, magnesium and cadmium; the internal impurities of particles are introduced in the synthesis process of diamond, mainly including iron, nickel, cobalt, manganese, cadmium, copper, etc. Impurities in the diamond powder will affect the surface properties of the powder particles, so that the product is not easy to disperse. Iron, nickel and other impurities will also make the product produce different degrees of magnetism, the application of powder.
, Impurity detection method
There are many impurity content detection methods of diamond powder, including weight method, atomic emission spectroscopy, atomic absorption spectroscopy, etc., different detection methods can be selected according to different requirements.
gravimetric analysis
The weight method is suitable for the analysis and detection of the total impurity content (excluding combustible volatile substances at burning temperature). The main equipment includes mafer furnace, analytical balance, porcelain crucible, dryer, etc. The test method for impurity content in the micropowder product standard is high temperature burning loss method: sample according to the provisions and take the test sample into the crucible with constant weight, place the crucible containing the sample to be tested in the furnace with 1000℃ to constant weight (temperature allowed + 20℃), the residual weight is miscellaneous mass, and the weight percentage is calculated.
2, atomic emission spectrometry, atomic absorption spectroscopy
Atomic emission spectroscopy and atomic absorption spectroscopy are suitable for the qualitative and quantitative analysis of trace elements.
(1) Atomic emission spectrometry: it is an analytical method for qualitative or quantitative analysis of the characteristic radiation line generated by the electron transition from the external energy of various chemical elements. The atomic emission method allows for the analysis of about 70 elements. In general, the measurement of components below 1% can accurately measure the ppm level trace elements in diamond powder. This method is the earliest produced and developed in optical analysis. Atomic emission spectrometry plays an important role in the qualitative and quantitative analysis of various modern materials. It has the advantages of multi-element simultaneous detection ability, fast analysis speed, low detection limit and high accuracy.
(2) Atomic absorption spectroscopy: when the radiation emitted by a specific light source passes through the atomic vapor of the element to be measured, it is absorbed by the ground state atoms, and the measured absorption degree can be measured for elemental analysis.
Atomic absorption spectrometry and it can complement each other and cannot be replaced with each other.
3. Factors affecting the measurements of the impurities
1. Effect of sampling volume on the test value
In practice, it is found that the sampling amount of diamond powder has a great influence on the test results. When the sampling amount is 0.50g, the average deviation of the test is large; when the sampling amount is 1.00g, the average deviation is small; when the sampling amount is 2.00g, although the deviation is small, the test time increases and the efficiency decreases. Therefore, during the measurement, blindly increasing the sampling amount does not necessarily improve the accuracy and stability of the analysis results, but also will greatly extend the operation time and reduce the work efficiency.
2. The influence of particle particle size on impurity content
The finer the particle of diamond powder, the higher the impurity content in the powder. The average particle size is 3um in fine diamond powder in production, due to the fine particle size, some acid and base insoluble materials mixed in raw materials are not easy to separate, so it settles into fine particle powder, thus increasing the content of impurities. Moreover, the more fine the particle size, the more in the manufacturing process, the more impurities into the external, such as dispersant, settling liquid, production environment of dust pollution impurities in the study of powder sample impurity content test, we found that more than 95% of the coarse-grained diamond powder products, its impurity content below 0.50%, more than 95% of fine-grained powder products its impurity content below 1.00%. Therefore, in the powder quality control, the fine powder should be less than 1.00%; the impurity content of 3um should be less than 0.50%; and two decimal places should be retained after the impurity content data in the standard. Because with the progress of powder manufacturing technology, the impurity content in the powder will gradually reduce, a large part of the impurity content of coarse powder is below 0.10%, if only one decimal place is retained, its quality can not effectively distinguish.
This article is sourced from the "superhard material network"
Post time: Mar-20-2025
