SMD Ceramic Pipe with steel pipe fittings as the matrix, the use of imported rubber as a binder, lined with hard ceramic pieces, will be hard ceramic film and the base tube bonded together, strong adhesion, good wear resistance. Mainly used in power plant pulverized coal, ash slag, mine powder, tailings, backfill, coal, concentrator of coal, coking plant coke, sintering plant materials transportation.
SMD Ceramic Features:
Wear-resistant hard ceramic patch is based on Al2O3 as raw material, rare metal oxides as solvents, by 1730 ℃ High-temperature sintering made of special corundum ceramics, hardness in hv1400-1600. With high abrasion resistance, it is suitable for the environment with serious wear. Can withstand a certain impact, can work under the conditions of poor working environment. Wear-resistant ceramic patches are 280 times times the wear resistance of manganese steel. HxW High-temperature Inorganic adhesive is our company procurement of imported binders. Steel and ceramics have excellent adhesion, process and thixotropy, can be cured at room temperature, with considerable strength and toughness, high heat resistance and aging resistance.
Ceramic film with high-temperature wear-resistant adhesive paste to the pipe, played a wear-resistant role, the pipeline is generally white. Generally used for large diameter pipes
Advantages: Ceramic SMD Wear-resistant pipe good wear resistance (than self-burning), Long service life
Production process
1, the process from the traditional direct paste into the use of each circle of the wrong seam arch installation, after heating curing, forming a solid anti-wear layer. The product is suitable for pneumatic conveying powder, under 350 ℃ under the high temperature environment for long term operation is not aging, do not fall off.
2, Spot welding process is the use of high temperature strong adhesive to the middle of the hole in the alumina ceramic plate paste in the pipe wall, coupled with the spot welding process through the small holes will be firmly welded ceramics in the steel tube wall. To protect the solder joint, the top is then spinning the ceramic cap.
Ceramic Patch Tube Features:
1, high hardness
Rockwell Hardness is hra85-90, the hardness is second only to Diamond.
2. Good abrasion resistance
According to the authority of testing, erosion wear in the case of wear-resistant ceramics is dozens of times times the ordinary steel.
3. Good impact resistance
Ceramics through toughening formula can form a strong crystal bond, so that the impact of alumina ceramics greatly enhanced.
4, the liner is firmly not off
The use of each circle arch, longitudinal dislocation of the installation process, with strong wear-resistant ceramic high-temperature inorganic adhesive, in the effective avoidance of linear gap at the same time, to ensure that the liner firmly do not fall off.
5, the use of life long
We promise that the pipe's wear life is 5-10 years.
Ceramic SMD Wear-resistant tube performance depends mainly on the performance parameters of ceramic patches, the following on a variety of technical parameters are as follows:
Technical parameters of alumina ceramic patch
I. Electrical properties
Volume resistivity, DC breakdown strength, dielectric loss angle tangent value and dielectric constant.
1. Volume resistivity ρν of volume resistivity insulating material refers to the ratio of the DC electric field intensity to the current density of the sample volume current direction. ΡΝ=EV/JV (ΩCM), in the formula, the EV is the DC electric field intensity, JV is the current density. 95% Alumina Ceramics is an excellent electronic insulating material, the volume resistivity is very high, the national standard gb/t5593-1999 stipulates, 100 ℃, when Ρν≥1x1013ωcm;300℃, Ρν≥1x1010ωcm;500℃, ρν≥1x108ωcm. In fact, the volume resistivity of 95 porcelain produced in China is 1-2 higher than the above regulation. Instruments used to test volume resistance are usually high resistance gauges.
2. DC Breakdown Strength The DC breakdown strength of electrical insulating materials refers to the changes in the effect of the Applied DC electric field, mainly due to the internal structure changes. When the electric field intensity is up to a certain value, the internal structure is further changed and the insulation breakdown occurs. The national standard gb/t5593-1999 stipulates that 95% Alumina ceramics is under the DC condition to carry on the withstanding pressure test, when exerts the direct current voltage on the sample, causes the specimen to breakdown, the breakdown voltage value and the specimen average thickness ratio is called the direct current breakdown strength, the unit: kv/mm. The national standard gb/t5593-1999 the stipulation to be bigger than 18kv/mm. In fact, we can usually reach 30-40kv/mm.
3, dielectric constant insulation material in the alternating current dielectric polarization degree of a parameter, it is filled with some kind of insulating material capacitor and vacuum as the medium, the same electrode size of the capacitor capacitance ratio. It represents an intrinsic property of the material. GB stipulates that the test frequency is 1MHz, 95% alumina ceramic dielectric constant between 9-10.
4, dielectric loss angle tangent dielectric loss means that the material in the AC electric field, polarization or absorption, resulting in power loss, usually in the media materials have fever phenomenon. The size of the dielectric loss is expressed by the tangent of the dielectric loss angle. The national standard gb/t5593-1999 stipulates, the frequency is 1MHz, 95% alumina ceramics request achieves 4x10-4.
Second, thermal properties
1. The average linear expansion coefficient is one of the main performance indices of 95% alumina ceramics when the relative elongation at the unit temperature is increased. The national standard gb/t5593-1999 stipulates that the test temperature is 20-500℃,a as 6.5x10-6-7.5x10-6/℃, and A is 6.5x10-6-8x10-6/℃ when the test temperature is 20-800 ℃. As the ceramic parts are generally to be closed with metal parts, the expansion coefficient must be matched with the expansion coefficient of metallic materials.
2. Thermal shock resistance refers to the ability of ceramic materials to withstand the urgent cold and heat. 95% Alumina ceramic has good thermal shock resistance and can withstand high temperature and hot and cold without destroying the test. National Standard gb/t5593-1999 stipulates: 10 ceramic specimens into the 800±10℃ furnace, heat preservation for 30 minutes, take out on the asbestos plate, natural cooling to room temperature, and then put the sample into 800 ℃ furnace, according to the above provisions, a total of 10 times, Finally in the 1% concentration of the magenta solution leaching to 3 minutes, remove with tap water wash, dry, under the light observation samples, if 10 samples are no cracks, cracking phenomenon, the performance of qualified.
III. Mechanical Properties
Mechanical properties refer to the ability of a material to act without destroying it under mechanical force. Strength, flexural strength and compressive strength are usually different according to the direction of the force and the stress point.
95% the tensile strength of alumina ceramics is generally more than 160MPA, usually greater than the best sealing strength. There are no technical specifications for the tensile strength and compressive strength of 95% alumina ceramics in the national standard gb/t5593-1999 regulations. National standard gb/t5593-1999 95% alumina ceramic flexural strength of 280MPA.
Iv. Other performance
1, Volume density 95% alumina ceramic bulk density and the choice of raw materials, porcelain technology has a great relationship. In the national standard gb/t5593-1999 requirements, 95% alumina ceramic volume density above 3.60g/cm3. In fact, the molding method of porcelain is different, 95% alumina ceramic density difference is big, usually hot-pressing casting and grouting method forming, the density is 3.60-3.70 g/cm3, when static pressure molding, 3.70 g/cm3, gel molding can reach 3.73 g/cm3.
2, air tightness of 95% alumina ceramics for microwave devices, vacuum switch tubes, etc., requires high vacuum gas tightness. In the electronic industry standard sj/t11246, the sealing part of the leakage rate Qk≤1x10--11pa m3/s. In fact, it also stipulates the ceramic leakage rate to meet the above standards.
3. Chemical stability 95% The chemical stability of alumina ceramics is characterized by its ability to resist the corrosion of various chemical reagents. The ability of acid-resistant reagent etching is called acid resistance, and the ability of alkali-resistant reagent etching is called alkali resistance. The national standard gb/t5593-1999 stipulates that the specimen is placed in 1:9 hydrochloric acid or 10% sodium hydroxide solution, the solution heats up to 100 ℃, the Heat preservation 1h. Acid-resistant requirements kh≤7mg/cm2, alkali-resistant requirements kn≤0.2mg/cm2.
4, the microstructure of ceramic microstructure refers to the crystal phase (main crystal phase, Zhijing phase), glass phase, gas phase, grain boundary composition, content, distribution, shape, particle size distribution, uniformity, defects, interphase matter, domain structure and other relationships. The microstructure is closely related to the porcelain making process, which directly affects the ceramic properties and is a research method to improve the ceramic quality and improve the process.
Five, 95% alumina ceramic-Metal sealing properties
95% Alumina ceramics, as a kind of structural ceramics, should be sealed with metal to form a part. Especially for 95% alumina ceramics used in microwave devices and vacuum development tubes, the ceramic-metal sealing properties are usually evaluated as important indexes. Evaluation of the content: ceramic-metal sealing performance requirements of high strength, while the need for better air tightness. In the electronic industry standard sj/t11246 "vacuum switch tube ceramic shell" stipulates that the average sealing strength, the use of standard porcelain seal, Σa≥90mpa, the use of three-point method test, Σa≥90mpa. Air tightness of sealing parts, helium leakage rate qk≤1x10-11pam3/s
