According to metal powder supplier, add silicon powder

According to metal powder supplier, add silicon powder can change some of the important physical performance of concrete, silica particles can be filled with a relatively greater porosity of the cement particles, reduce the pore volume, but the silicon powder’s specific surface area on the workability have a great impact.

Thus, the general water consumption should increase with the silicon powder content increased. But in order to maintain the same liquidity, while adding silicon powder are generally required to join superplasticizer. To improve the workability in cement consumption <300 kg/rn2, adding silicon powder can improve its cohesiveness, reduce the secretion of water. Because the specific surface area of the silicon powder is very large, many of the free water in the fresh concrete are bound by silicon powder particles, can greatly reduce the secretion of water. Reducing the accumulation of moisture in the interface, improve the interfacial bonding properties.

When larger slump, vibration time is relatively long, silicon powder concrete is not easy to segregate. Silicon powder concrete increases the risk of plastic shrinkage cracking, especially in the higher evaporation rate. Plastic shrinkage cracking can occur in the concrete pouring until plastering start to solidify, occurs mostly in the concrete close to the initial setting. In order to prevent the plastic cracking, the concrete must be covered to prevent rapid evaporation surface covering the available sacks or plastic film or the curing agent, or use the spray method to reduce evaporation, some can retard evaporation special admixtures, also be used to reduce plastic shrinkage cracking danger.

In the case of no superplasticizer also can delay the setting time, especially in case of high content of silicon powder. When adding silicon powder to improve the strength of concrete, the difference of additives, the setting time is different, and some of them shortening for Mechanical structure series 1-2 h, some did not increase significantly, some delay for 2 h. Reduce the air content: due to the specific surface area of the silicon powder is higher, in the case of the same dose air entraining agent, the gas containing should be reduced, although use superplasticizer will be the same. Silicon powder instead of cement can reduce the heat of hydration temperature rise.

Silicon powder cement show up thermal peak is slightly earlier than cement without silicon powder, but the total heat release below the cement without silicon powder. Make the grout and aggregate interfacial transition zone improved, and make pore structure refinement are caused the intensity increased. However, due to the water consumption increased, to offset part of the strength growth. After adding silicon powder, about the silicon powder concrete strength increased degree is available to measure by efficiency index. The so-called efficiency index is the replacement of cement with silicon powder, the contribution of 1 part silicon powder to concrete strength may be equivalent to 2 to 5 times strength of cement can be produced, the multiple is called the efficiency index of the silicon powder. With the silicon powder content increased, its efficiency index gradually decreased, when the silicon powder dosage> 20%, the efficiency index was significantly decreased, while > 30%, the strength of the concrete may even decline. Therefore, the dosage is usually less than 20%. When silicon powder dosage is too high, the fresh concrete become very viscous increase the construction pouring difficulty. At the same time, the price of silicon powder is higher than cement, to meet the design strength of concrete or other performance requirements under the premise, with less doped is appropriately, in high-performance concrete, the usual dosage is generally between 5%-15%.

Silicon powder concrete shrinkage and autogenous shrinkage increased by water-cement ratio reduce. General silicon powder concrete perform that drying shrinkage increases in early stage and reduce in later stage. In order to reduce the early dry shrinkage of silicon powder concrete, can extend the moist curing time, dubbed the silicon powder slurry agent or incorporated into the appropriate expansion agent and so on.

The data shows that the volume of copper annual increases

The data shows that the volume of copper annual increases more than 10 percent in recent years. In the development prospects of Chinese domestic market, Copper powder is an important powder material only after iron powder. Copper is widely used in iron-based copper-based powder metallurgy parts. The average annual growth of Chinese copper powder is more than 10%

In the friction materials industry, the usage amount of copper powder is more than 1300 tons per year. In the diamond tool industry, there are more than 100 companies whose usage amount of copper powder (FCu) is more than 20 tons. And thus the preliminary estimates the annual consumption of the diamond tool industry of copper powder in 2000-3000 tons. Electrical Alloy industry, the amount of electrolytic copper powder is 200 tons.

In addition, the electric carbon industry as well as metallic pigment coating of conductive rubber and the copper slurry, the demand for copper powder is also increasing. In 2011, Chinese copper powder imports are 23,274 tons, it is an increase of 22.78% over the previous year.

The statistics of nonferrous metals association show that demand for the world per year of copper and copper alloy powder in more than 100,000 tons, of which about half the annual output of the total demand in North America from the foreign market demand. Meanwhile, other Southeast Asian countries, copper powder is mainly used for material processing, the demand has expanded each year, but no metal powder supplier.

Copper and its alloys powder metallurgy products have good electrical conductivity, thermal conductivity, corrosion resistance properties, surface finish and non-magnetic, etc. They are widely used in friction materials, oil bearings, electrical contact material, conductive material, diamond products, filtration and mechanical parts. They are also widely applied in automotive, appliance, electronics, communications and other fields. Electrolytic copper powder with its excellent physical properties and chemical purity is often used in diamond tools, powder metallurgy, friction materials, carbon products, electrical alloys, metal coatings and pigments and electronic paste, conductive rubber and other products. For example, the amount of copper powder in automobile industry has reached over ten thousand tons. If taking into account the electronic, electrical and other industries, its has broader potential market.Source:http://www.mhcmp.com