Joining of Ceramic Components in the Green State via LPIM

2007 ◽  
Vol 29-30 ◽  
pp. 207-210 ◽  
Author(s):  
Rolf Waesche ◽  
Carl Paulick ◽  
Gabriele Steinborn ◽  
V. Richter ◽  
M. Werner
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Alumina Powder ◽  
Second Phase ◽  
Green State ◽  
Ceramic Components ◽  
Molded Parts

It has been successfully demonstrated that ceramic materials can be joined in the green state without a second phase by using low pressure injection molded parts. The investigation of the joining interface revealed that a high quality interface can be achieved by carefully adjusting the different manufacturing steps. The use of monomodal particle size distribution in the used powder CT3000SG is inferior to a broader particle size distribution obtained by replacing 33% of the finer alumina powder by coarser CT1200SG. In this way the dewaxing process is significantly improved when the wall thickness of the part exceeds 3 mm. The investigation of the mechanical properties of the joined and sintered parts revealed, that the bending strength of the joined specimens achieved about 80 % of the unjoined, monolithic specimens.

Effect of the Ball Milling on the Microstructure and Mechanical Properties of AlN/Cu Composite

2015 ◽  
Vol 816 ◽  
pp. 15-20
Author(s):  
Qian Yu ◽  
Mei Hui Song ◽  
Yan Li ◽  
Xiao Chen Zhang
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ball Milling ◽  
Bending Strength ◽  
Rotation Speed ◽  
Mixing Time ◽  
Composite Powders

AlN/Cu composite powder was prepared by ball milling method. Laser particle size analyzer, X-ray diffraction and scanning electron microscopy analysis were performed to study AlN/Cu composite powders. The effects of rotation speed, mixing time, and ball to powder weight ratio (BPR) on the particle size distribution, composition, and morphology were investigated. Results showed that the best ball milling parameters were the rotation speed of 200r/min, mixing time of 6 hours and BPR 10:1. In this best condition, AlN/Cu composite powders would be obtained with optimum particle size distribution and morphology. Then composite powders were pressed at 500MPa and sintered at 1000°C in N2atmosphere. Finally, the composite with an AlN content of 33wt% showed the bending strength of 370MPa, Vikers hardness HV154, thermal conductivity of 182.7W/m°C and electrical conductivity of 3.08MS/m. However, the composite with an AlN content of 25wt% showed the bending strength of 329MPa, Vikers hardness HV122, thermal conductivity of 195W/m°C and electrical conductivity of 6.54MS/m.

scholarly journals INVESTIGATION OF SINTERING FEATURES OF CERAMIC MATERIALS BASED ON HYDROXYAPATITE AND ITS SUBSTITUTED FORMS

2020 ◽  
pp. 535-545
Author(s):  
Екатерина Анатольевна Богданова ◽  
Ирина Андреевна Веретенникова
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Specific Surface ◽  
Size Distribution ◽  
Surface Area ◽  
Ceramic Materials ◽  
Fluoride Ions ◽  
Apatite Phase ◽  
Grain Distribution ◽  
Initial Compaction

Порошки стехиометрического и фторзамещенного гидроксиапатита с повышенной активностью к спеканию (температура начала уплотнения составляет 600°С) синтезированы методом осаждения из раствора. Исследованы свойства синтезированных порошков и керамики после обжига. Показано, что введение фторид-ионов позволяет термически стабилизировать фазу апатита до температуры 1000°С, повысить степень дисперсности и площадь удельной поверхности, почти в три раза увеличить микротвердость материала. Сопоставление распределения частиц по размерам в синтезированных порошках и распределения зерен в спеченной керамике подтвердили наследование керамикой наноструктуры исходных порошков. Stoichiometric and fluorsubstituted hydroxyapatite powders with increased sintering activity (the initial compaction temperature is 600°C) were synthesized by precipitation from solutions. Properties of synthesized powders and ceramics after firing were investigated. It is shown that the introduction of fluoride ions can thermally stabilize the apatite phase to a temperature of 1000 °C, increase the degree of dispersion and the specific surface area, and almost three times increase the microhardness of the material. Comparison of the particle size distribution in synthesized powders and the grain distribution in sintered ceramics confirmed that ceramics inherited the nanostructure of the original powders.

Coarse Second Phase Particle Size Distribution of UFG Al Alloys Processed by Severe Plastic Deformation: Effect on Cavitation during Superplastic Deformation

2007 ◽  
Vol 539-543 ◽  
pp. 2859-2864 ◽  
Author(s):  
Kyung Tae Park ◽  
Eui Gil Lee ◽  
Won Jong Nam ◽  
Yong Sin Lee
Keyword(s):  
Plastic Deformation ◽  
Particle Size ◽  
Severe Plastic Deformation ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Superplastic Deformation ◽  
Phase Particle ◽  
Theoretical Models ◽  
Al Alloys ◽  
Second Phase

Two commercial Al alloys having different second phase particle distributions were subjected to severe plastic deformation (SPD) via equal channel angular pressing with or without subsequent cold rolling, and the effect of such SPD on the particle size distribution of the alloys was investigated. The particles larger than ∼ 3 μm were fragmented into several smaller ones by SPD. Contrarily, those smaller than ∼ 3 μm were hardly broken up by SPD but their distribution became more uniform. Along with these findings and the theoretical models for cavity nucleation at second phase particles, the cavitation behavior of ultrafine grained Al alloys during low temperature or high strain rate superplastic deformation was discussed.

Particle Size Distribution Analysis of an Alumina Powder: Influence of Some Dispersants, pH and Supersonic Vibration

2005 ◽  
Vol 498-499 ◽  
pp. 73-78 ◽  
Author(s):  
C.J. Papini ◽  
Walter Kenji Yoshito ◽  
Douglas Gouvêa ◽  
Ricardo Mendes Leal Neto
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Electrostatic Force ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Alumina Powder ◽  
Distribution Analysis ◽  
Laser Scattering ◽  
Dispersion Condition

It is well known that colloidal powder particles (between 1 mm and 0.001 mm) tend to agglomerate due to electrostatic forces. Then assuring an optimal dispersion condition is essential for good particle-size analysis results, since aggregates or weak agglomerates can be measured as single particles. In this paper the particle size distribution of an alumina powder A1000SG (ALCOA) was measured using distinct dispersion procedures. Distilled water was used as dispersant liquid in the pure state and with additives (citric acid and Duramax D-3005). Dispersion by supersonic vibration was also investigated, but only the application time was varied. Particle size analysis was accomplished by laser scattering technique and the dispersion condition was evaluated through zeta potential. The results showed that the Duramax’s electrosteric impediment is more efficient than citric acid’s electrostatic force, thereby providing better dispersion. Although useful, the supersonic vibration was not good enough to assure an optimal dispersion, at least for the material tested here.

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