Co-sintered ceramic converter for transmissive laser-activated remote phosphor conversion

2022 ◽  
Vol 120 (2) ◽  
pp. 021104
Author(s):  
Alan Lenef ◽  
John F. Kelso ◽  
Jeffery Serre ◽  
Ashish A. Kulkarni ◽  
Douglas Kinkenon ◽  
...  
Keyword(s):  
Sintered Ceramic ◽  
Remote Phosphor

Effects of compression during formation on the microstructure of composite hydroxylapatite/plaster implants for bone reconstruction

1988 ◽  
Vol 46 ◽  
pp. 750-751
Author(s):  
J. Hanker ◽  
K. Cowden ◽  
R. Noecker ◽  
P. Yates ◽  
N. Georgiade ◽  
...  
Keyword(s):  
Cosmetic Surgery ◽  
Glass Plate ◽  
Surgical Reconstruction ◽  
Equal Weight ◽  
Sintered Ceramic ◽  
Setting Times ◽  
Excess Water ◽  
Mixture Prior ◽  
Mechanical Strengths ◽  
Calcium Sulfate Hemihydrate

Composites of plaster of Paris (PP) and hydroxylapatite (HA) particles are being applied for the surgical reconstruction of craniofacial bone defects and for cosmetic surgery. Two types of HA particles are being employed, the dense sintered ceramic (DHA) and the porous, coralline hydroxylapatite (PHA) particles. Excess water is expressed out of the moistened HA/PP mixture prior to implantation and setting by pressing it in a non-tapered syringe against a glass plate. This results in implants with faster setting times and greater mechanical strengths. It was therefore of interest to compare samples of the compressed versus noncompressed mixtures to see whether or not any changes in their microstructure after setting could be related to these different properties.USG Medical Grade Calcium Sulfate Hemihydrate (which has the lowest mortar consistency of any known plaster) was mixed with an equal weight of Interpore 200 particles (a commercial form of PHA). After moistening with a minimum amount of water, disc-shaped noncompressed samples were made by filling small holes (0.339 in. diameter x 0.053 in. deep) in polypropylene molds with a microspatula.

Scanning electron microscopy of composite hydroxylapatite/plaster implants for bone reconstruction

1986 ◽  
Vol 44 ◽  
pp. 326-327
Author(s):  
J. S. Hanker ◽  
B. L. Giammara
Keyword(s):  
Tooth Extraction ◽  
Alveolar Ridge ◽  
Small Particles ◽  
Alveolar Ridge Augmentation ◽  
Sintered Ceramic ◽  
Ridge Augmentation ◽  
Fibrovascular Tissue ◽  
Infrabony Defects ◽  
Edentulous Patients ◽  
Scanning Electron

Nonresorbable sintered ceramic hydroxylapatite (HA) is widely employed for filling defects in jaw bone. The small particles used for alveolar ridge augmentation in edentulous patients or for infrabony defects due to periodontal disease tend to scatter when implanted using water or saline as the vehicle. Larger blocks of this material used for filling sockets after tooth extraction don't fit well. Studies in our laboratory where we compared bovine serum albumin, collagen and plaster of Paris as binders to prevent particle scatter during implantation suggested that plaster was most useful for this purpose. In addition to preventing scatter of the particles, plaster enables the formation of implants of any size and.shape either prior to or during surgery. Studies with the PATS reaction have indicated that plaster acts as a scaffold for the incorporation of HA particles into bone in areas where the implant contacts either host bone or periosteum. The shape and integrity of the implant is maintained by the plaster component until it is replaced over a period of days by fibrovascular tissue.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

Fabrication and characterization of highly textured (Bi,Pb)2Sr2Ca2Cu3Ox superconducting ceramics using high magnetic field and cold isostatic pressing

1995 ◽  
Vol 10 (10) ◽  
pp. 2433-2443 ◽  
Author(s):  
Wai Lo ◽  
R. Stevens ◽  
R. Doyle ◽  
A.M. Campbell ◽  
W.Y. Liang
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Cold Isostatic Pressing ◽  
Sintered Ceramic ◽  
Grain Alignment ◽  
Isostatic Pressing ◽  
Transmission Electron ◽  
Superconducting Ceramics ◽  
High Degree

High textured (Bi,Pb)2Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi,Pb)2Sr2Ca2Cu3Ox suspended in an organic medium by means of a high de magnetic field (6 T) at room temperature followed by cold isostatic pressing. The proportion of the (Bi,Pb)2Sr2Ca2Cu3Ox phase in the precursor powder was carefully controlled, and the characteristics of the powder, such as size distribution and morphology, were determined. A high degree of grain alignment was found in the specimens after the magnetic alignment, although the bulk density of the materials was low. Cold isostatic pressing substantially increased the density of the magnetically prealigned specimens which also resulted in a slight decrease in the degree of grain alignment. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction due to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered ceramic have been studied using texture goniometry, high resolution scanning electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.

Investigation of the influence of the mode of heat treatment of the initial powder on the efficiency of sintering zirconium ceramics by dilatometry

2021 ◽  
Vol 103 (3) ◽  
pp. 17-24
Author(s):  
S. Shevelev ◽  
◽  
E. Sheveleva ◽  
O. Stary ◽  
Keyword(s):  
Thermal Annealing ◽  
Zirconium Dioxide ◽  
Annealing Temperature ◽  
Average Particle Size ◽  
Average Particle ◽  
Sintered Ceramic ◽  
Tetragonal Modification ◽  
Thermal Sintering ◽  
Powder Compacts ◽  
High Degree

Using methods of synchronous thermal and X-ray structural analyzes applied to zirconium dioxide powders partially stabilized with yttrium obtained by chemical coprecipitation the processes of dehydration of these powders during annealing in air have been investigated. Using the dilatometry method, the regularities of compaction of powder compacts have been investigated with thermal sintering. It was found that the resulting powders mainly consist of the tetragonal modification zirconium dioxide and are nano-sized. The average particle size was 25 nm. The resulting powders are characterized by a high degree of agglomeration. It is shown that an increase in the thermal annealing temperature from 500 to 700ºС leads to partial baking of individual particles inside the agglomerate, and causes the formation of hard agglomerates, the presence of which complicates the processes of compaction and subsequent sintering. The presence of such agglomerates prevents the production of ceramics with high mechanical characteristics: density and porosity. Thermal annealing temperature increase leads to a decrease in the density of the sintered ceramic and a decrease in its hardness.

scholarly journals Effect of wear from cleaning operations on sintered ceramic surfaces: Correlation of surface properties data with touch perception and digital image processing

Wear ◽  
2017 ◽  
Vol 390-391 ◽  
pp. 355-366 ◽  
Author(s):  
Agnese Piselli ◽  
Margherita Basso ◽  
Michele Simonato ◽  
Riccardo Furlanetto ◽  
Alberto Cigada ◽  
...  
Keyword(s):  
Image Processing ◽  
Surface Properties ◽  
Digital Image Processing ◽  
Digital Image ◽  
Sintered Ceramic ◽  
Touch Perception ◽  
Ceramic Surfaces
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