Oxidation Behaviors of TiB2-TiCX and TiB2-TiCX/15SiC Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 179-183 ◽  
Author(s):  
De Gui Zhu ◽  
Hong Liang Sun ◽  
Yu Shu Wang ◽  
Liang Hui Wang
Keyword(s):  
Oxidation Resistance ◽  
Effective Temperature ◽  
Hot Isostatic Pressing ◽  
Ceramic Composites ◽  
Optical Micrograph ◽  
Different Temperatures ◽  
The Mean ◽  
Mean Time ◽  
Oxidation Behaviors

Fully dense samples of TiB2-TiCX and TiB2-TiCX/15SiC ceramic composites were fabricated by in-situ synthesis under hot isostatic pressing from TiH2, B4C and SiC powders. Their oxidized behaviors at different temperatures were tested. Optical micrograph studies and thermo-gravimetric analyses show that the highest effective temperature of oxidation resistance is 700°C for TiB2-TiCX, and 1100°C for TiB2-TiCX/15SiC. The weight gain of TiB2-TiCX/15SiC below 1100°C is quite low, and it rises up suddenly when the temperature reaches 1200°C. Thus, the highest effective temperature of oxidation resistance is 1100°C for TiB2-TiCX/15SiC. The oxidation dynamic curves of TiB2-TiCX/15SiC ceramics accord with the parabola’s law. The activation energy of TiB2-TiCx/15SiC (189.87kJ.mol-1) is higher than that of TiB2-TiCx (96.44kJ.mol-1). In the oxidation process of TiB2-TiCx/15SiC, TiB2 reacts with oxygen and generates TiO2 and B2O3 at first. A layer of whole homogeneous oxide film cannot be formed, in the mean time, the oxidation of TiC begins. When temperature goes up to 1000°C, TiC phase is totally oxidized. SiC is oxidized to SiO2 at about 900°C, Meanwhile, TiO2 forms denser film than B2O3, which grows and covers the surface of the material, and gives better property of oxidation resistance.

Oxidation Behavior of Ti3SiC2-SiC Ceramic Composites

2007 ◽  
Vol 561-565 ◽  
pp. 687-691
Author(s):  
De Gui Zhu ◽  
Zhi Gang Wang
Keyword(s):  
Oxidation Resistance ◽  
Hot Isostatic Pressing ◽  
Ceramic Composites ◽  
Temperature Oxidation ◽  
Parabolic Law ◽  
Sic Ceramic ◽  
Long Time ◽  
Better Than ◽  
Oxidation Behaviors

The high temperature oxidation behaviors of the Ti3SiC2-SiC ceramic composites fabricated by in situ synthesis under hot isostatic pressing were studied by DSC. The results show that the growth of the oxide scales on Ti3SiC2-SiC ceramic composites obeys a parabolic law in air. The oxidation resistance at 1400°C is better than that at 1200°C for long time. The oxidation resistance of the Ti3SiC2-SiC ceramic composites is much higher than that of monolithic Ti3SiC2. The mechanism of oxidation of Ti3SiC2-SiC ceramic composites is discussed.

ELECTROCHEMICAL MIGRATION BEHAVIOR OF Sn-3.0Ag-0.5Cu SOLDER ALLOY UNDER THIN ELECTROLYTE LAYERS

2019 ◽  
Vol 26 (06) ◽  
pp. 1850208 ◽  
Author(s):  
BOKAI LIAO ◽  
WENFENG JIA ◽  
RUIYAN SUN ◽  
ZHENYU CHEN ◽  
XINGPENG GUO
Keyword(s):  
Solder Alloy ◽  
Electrochemical Migration ◽  
Migration Behavior ◽  
Time To Failure ◽  
Sac305 Solder ◽  
Maximum Value ◽  
The Mean ◽  
Mean Time ◽  
Observation Results

The electrochemical migration (ECM) behavior of Sn-3.0Ag-0.5Cu solder alloy under thin electrolyte layers was investigated using a technique based on the coupling of in situ electrochemical measurements and optical observation. Results showed that the mean time to failure first increased and then decreased as thickness of the electrolyte layer increased, the maximum value was present at 200[Formula: see text][Formula: see text]m. The higher the bias voltage applied, the faster was the rate of dendrite growth. And, Sn leaded the ECM of SAC305 solder alloy. Mechanisms relevant have been proposed to explain the ECM behavior of Sn-3.0Ag-0.5Cu solder alloy.

scholarly journals Reactive sintering of B4c-TiB2 composites from B4 and TiO2 precursors

2020 ◽  
Vol 14 (4) ◽  
pp. 329-335
Author(s):  
Pavol Svec ◽  
Zuzana Gábrisová ◽  
Alena Brusilová
Keyword(s):  
Fracture Toughness ◽  
Boron Carbide ◽  
Titanium Diboride ◽  
Sintering Temperature ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Reactive Sintering ◽  
Different Temperatures ◽  
Carbide Matrix

The effect of sintering temperature in the interval from 1775 to 1850?C on the density, microstructure, hardness and fracture toughness of ceramic composites consisting of a boron carbide matrix and titanium diboride secondary phase was studied. The composites were hot pressed using in situ reaction between boron carbide and 40 wt.% of titanium dioxide additive. The samples were hot pressed at different temperatures but for the constant time of 60min, under the pressure of 35MPa in vacuum of 10 Pa. Both Vickers hardness and fracture toughness of the composites increased with the sintering temperature.Maximal hardness of 29.8GPa and fracture toughness of 6.9MPa?m1/2 were achieved for the composite with 29.6 vol.% of titanium diboride secondary phase sintered at the highest sintering temperature of 1850?C.

Phase Interactions in Monoclinic Zirconia Reinforced Hydroxylapatite Bioceramics

Volume 1 ◽  
2004 ◽  
Author(s):  
Celaletdin Ergun ◽  
Zafer Evis ◽  
Robert H. Doremus
Keyword(s):  
Thermal Analysis ◽  
Tricalcium Phosphate ◽  
Hot Pressing ◽  
Monoclinic Zirconia ◽  
Pure Zirconia ◽  
Different Temperatures ◽  
The Mean ◽  
Zirconia Phase ◽  
Mean Time

Hydroxylapatite composites with pure zirconia were prepared with pressureless air sintering and hot pressing for 1 hour at different temperatures between 900°C and 1300°C. The interaction between the phases was monitored with XRD and thermal analysis. At sintering temperatures higher than 1000°C, an apparent Ca diffusion occurred from hydroxylapatite to pure zirconia phase and changed its structure from monoclinic to tetragonal/cubic. In the mean time, hydroxylapatite decomposed and formed tricalcium phosphate. Also, a reaction was occurred at 1220°C between hydroxylapatite and zirconia phase forming CaZrO3. The existence of air in the processing environment increased the reactivity between hydroxylapatite and zirconia.

scholarly journals Use of Autologous Leucocyte- and Platelet-Rich Plasma (L-PRP) in the Treatment of Aural Hematoma in Dogs

2021 ◽  
Vol 8 (9) ◽  
pp. 172
Author(s):  
Roberta Perego ◽  
Eva Spada ◽  
Elena Moneta ◽  
Luciana Baggiani ◽  
Daniela Proverbio
Keyword(s):  
Clinical Effect ◽  
Platelet Rich Plasma ◽  
Healing Process ◽  
Short Term ◽  
Clinical Resolution ◽  
The Mean ◽  
Clinical Healing ◽  
Mean Time

Leukocyte- and platelet-rich plasma (L-PRP) can accelerate the healing process by providing increased concentrations of platelet-derived growth factors. The objective of this study was to evaluate the clinical effect of L-PRP in the treatment of canine aural hematomas associated with otitis externa. Twenty mL of citrated whole blood was collected from each of the 17 dogs included and autologous L-PRP was produced. The aural hematoma was drained and 0.5–1 mL of L-PRP was injected. The dogs were examined weekly until 7 days after complete clinical healing. A final clinical follow-up was performed 6 weeks after the first treatment with L-PRP. If there was recurrence of the aural hematoma at the first follow-up, the treatment was repeated. In total, 2/17 cases were lost after the first follow-up. In 5/17 dogs, a short-term recurrence occurred. In 12/15 cases, complete clinical resolution was achieved with a single L-PRP application (Group A1) and in 3/15 with two treatments (Group A2). The mean time to complete clinical resolution was 16 ± 8.7 days (A1) and 23.3 ± 4 days (A2), respectively. No side effects were reported. The in situ administration of autologous L-PRP resulted in a complete resolution of the aural hematoma in all dogs that completed the clinical trial.

scholarly journals Morphological characterization and germination of Syagrus schizophylla (Mart.) Glass. (ARECACEAE)

2019 ◽  
Vol 10 (1) ◽  
pp. 54-64
Author(s):  
Rômulo André Beltrame ◽  
Janie Mendes Jasmim ◽  
Henrique Duarte Vieira
Keyword(s):  
Water Absorption ◽  
Average Length ◽  
Seedling Emergence ◽  
Morphological Characterization ◽  
Palm Tree ◽  
Average Width ◽  
Different Temperatures ◽  
Emergence Curve ◽  
The Mean ◽  
Mean Time

The interest in Syagrus schizophylla as an ornamental palm tree and the demand for conservation and preservation of the species led to this research. The objective was to study the physiological characteristics of its germination at different temperatures, as well as the morphological and biometrical characterization of diaspores and seedlings at the initial stages of growth and development. The research was divided into two experiments. In the first one, the aim was to identify the water absorption phases of seeds during germination under five scarification treatments as follows: intact diaspores, scarified diaspores, diaspores with endocarp rupture and intact seeds. In the second experiment, germination was tested at 25, 30 e 25 - 35 ºC; the first germination count, seedling emergence, abnormal seedlings, non-germinated seeds, the emergence curve, the emergence speed index and the mean time of emergence were evaluated. Afterwards, the morphological and biometrical characteristics of diaspores and seedlings were described. The water absorption curve observed under the different scarification treatments showed different water absorption patterns. Emergence percentages were 53, 61 and 47% at 25, 30 and 25 - 35 ºC, respectively. The highest emergence speed index was obtained at 30 ºC. The mean time of emergence was 30 days, approximately, under all the temperatures tested. The diaspores showed a great variability in both shape and size, presenting a globular to ovoid shape with an average length of 2.44 cm and an average width of 1.39 cm. The germination can be classified as hypogeal crypto cotyledonal of the remote-tubular type.

Phase Interaction in Hydroxylapatite/LaPO4 Composite

2006 ◽  
Author(s):  
Celaletdin Ergun ◽  
John W. Halloran ◽  
Chang-Jun Bae ◽  
Filiz C¸ınar S¸ahin
Keyword(s):  
Tricalcium Phosphate ◽  
Xrd Analysis ◽  
Phase Interaction ◽  
Lanthanum Phosphate ◽  
Phosphate Phase ◽  
Different Temperatures ◽  
The Mean ◽  
Mean Time

Hydroxylapatite composites with lanthanum phosphate were prepared with pressureless air sintering for 2 hours at different temperatures between 500°C and 1300°C. The interaction between the phases was monitored with XRD analysis. At sintering temperatures higher than 700°C, hydroxylapatite and lanthanum phosphate phase reacted and formed Ca8 La2 (PO4)6O2 as byproduct. In the mean time, hydroxylapatite decomposed and formed tricalcium phosphate.

Intubation drug pack containing pre-filled syringes reduces the time to endotracheal intubation in a simulated paediatric emergency

2019 ◽  
Vol 6 (2) ◽  
pp. 105-107
Author(s):  
Sara Lawson ◽  
Christopher Flannigan ◽  
Carolyn Green ◽  
Lynsey Freeburn ◽  
Anne Burns ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Endotracheal Intubation ◽  
Paediatric Intensive Care Unit ◽  
Standard Care ◽  
Paediatric Hospital ◽  
Paediatric Emergency ◽  
The Mean ◽  
Mean Time

To determine if an intubation drugs pack containing pre-filled syringes can reduce the time to endotracheal intubation compared with standard care during a simulated paediatric emergency. Twenty doctors (10 consultants and 10 registrars) who worked in the paediatric intensive care unit or anaesthetic department of a tertiary paediatric hospital were asked to participate in an in situ simulated emergency paediatric intubation scenario. The participants were instructed to prepare and administer intubation medications. They were randomised to either an intubation drug pack, containing pre-filled syringes or to standard care where each of the drugs had to be individually drawn-up. The mean time to intubation when using the pre-filled syringes of 159.5 s was over three times faster than with standard care of 497.5 s (p<0.001), allowing intubation to occur on average 5 min and 38 s earlier. Utilising an intubation drug pack containing pre-filled syringes significantly reduced the time from decision to intubate to intubation in a simulated paediatric emergency. This applied irrespective of clinical experience with registrars utilising the pre-filled syringes outperforming consultant anaesthetists when they used standard care.

Fabrication and Oxidation Resistance Property of SiC Coatings on Surface of Graphite by Chemical Liquid Deposition

2011 ◽  
Vol 55-57 ◽  
pp. 82-86
Author(s):  
Yun Hu Zhu ◽  
Hao Ran Geng ◽  
Guang Li Chen
Keyword(s):  
Optimum Condition ◽  
Mass Loss ◽  
Oxidation Resistance ◽  
Deposition Temperature ◽  
Test Results ◽  
Different Temperatures ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition ◽  
Sic Coatings ◽  
Oxidation Behaviors

SiC coatings were fabricated by the Rapid Chemical Liquid Deposition (RCLD) on the surface of graphite, the influence of deposition temperature on the microstructure of SiC coatings was investigated, the oxidation behaviors of SiC coatings at different temperatures were analyzed. The results indicated that the optimum condition for the SiC coatings are at 1150°C, a smooth and dense coating will be obtained, the thickness of the coatings are between 80～120μm. The oxidation resistance test results indicated that after oxidation at 1000°C for 5h, the mass loss of the sample is only 21%.

Study on the Oxidation Kinetics of In Situ β-Sialon Bonded Al2O3-C Refractories

2014 ◽  
Vol 881-883 ◽  
pp. 1021-1025 ◽  
Author(s):  
Bin Xu ◽  
Hong Xi Zhu ◽  
Nai Peng ◽  
Cheng Ji Deng ◽  
Wen Jie Yuan
Keyword(s):  
Oxidation Rate ◽  
Reaction Rate ◽  
Diffusion Rate ◽  
Isothermal Oxidation ◽  
Different Temperatures ◽  
Rate Controlled ◽  
Kinetics Of ◽  
And Diffusion ◽  
Oxidation Behaviors

The oxidation behaviors and kinetics of in-situ β-Sialon bonded Al2O3-C refractories were investigated by TGA techniques via isothermal oxidation experiments at different temperatures. The results show that the oxidation process of in-situ β-Sialon bonded Al2O3-C refractories can be divided into three stages: oxidation reaction rate controlling stage, reaction and diffusion controlling stage, and diffusion controlling stage. The oxidation rate controlled by the reaction rate has no obvious changes as the temperature increases. The oxidation rate controlled by the reaction rate and the diffusion rate together has a trend of decline, so is the oxidation rate controlled by the diffusion rate.

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