Prebrazing of Ceramics by Plasma Spraying for Metal-Ceramic Joining

1998 ◽  
Author(s):  
A. Kara-Slimane ◽  
D. Treheux
Keyword(s):  
Plasma Spraying ◽  
Ceramic Surface ◽  
Interface Analysis ◽  
Residual Oxygen ◽  
Metal Ceramic ◽  
Brazed Joint

Abstract Traditionnal brazing ailoys does not wet ceramic and therefore are unusable for metal ceramic bonding. To overcome this problem, we have pre-metallized different ceramics (AI2O3, AIN, SiAION) by plasma spraying of copper on ceramics. The good wettability of AgCu or AgCuTi alloy on so-coated ceramics is explained by effect of residual oxygen at interface which favours the thermodynamic adhesion during brazing. The interface analysis showed that silver or titanium segregation occurs at ceramic surface and that, conversely, sprayed copper diffuses in the brazed joint

HREM and AEM study of Pt/SiC interface annealed at high temperature

1993 ◽  
Vol 51 ◽  
pp. 832-833
Author(s):  
J.S. Bow ◽  
L.M. Porter ◽  
M.J. Kim ◽  
R.W. Carpenter ◽  
R.F. Davis
Keyword(s):  
High Temperature ◽  
Image Data ◽  
Amorphous Layer ◽  
Atomic Resolution ◽  
Ceramic Surface ◽  
High Temperature Annealing ◽  
Ion Milling ◽  
Ceramic System ◽  
Residual Oxygen ◽  
Metal Ceramic

High temperature applications of SiC semiconductor devices will be essentially limited by the metal/SiC interface interconnect properties. Pt/SiC was reported to have more stable and better electrical properties than other metal/6H-SiC after annealing above 700°C under UHV condition. Some work on the Pt/SiC interface has been conducted by AES and other low spatial resolution surface techniques, but there is no detailed direct image data reported. Here, we characterize the microstructure of the Pt/SiC interface after high temperature annealing in UHV at near atomic resolution and reported the first nanospectroscopic energy loss data for the system.As-deposited Pt film is polycrystalline with grain size of 10 ± 3 nm (Fig.l). The thin amorphous layer visible at the interface in Fig.l, gradually disappearing in the thick regions, was attributed to oxygen-induced ion-milling damage. Similar results were observed frequently in other metal/ceramic system. We consider the amorphous layer to be due to residual oxygen on the ceramic surface during synthesis, since trace oxygen was only detected at the as-deposited Pt/6H-SiC interface.

scholarly journals Influence of Sealing of the Screw Access Hole on the Fracture Resistance of Implant-Supported Restorations

2016 ◽  
Vol 27 (2) ◽  
pp. 148-152 ◽  
Author(s):  
Rodrigo de Paula Pereira ◽  
Cibele Oliveira de Melo Rocha ◽  
José Maurício dos Santos Nunes Reis ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Fracture Resistance ◽  
Resin Composite ◽  
Filling Material ◽  
Ceramic Surface ◽  
Access Hole ◽  
Mandibular Molar ◽  
Significant Difference ◽  
Metal Ceramic ◽  
One Way Anova ◽  
Ceramic Implant

Abstract The purpose of this study was to assess the influence of sealing of the screw access hole (SAH) on the fracture resistance of metal-ceramic implant-supported restorations. UCLA abutments were used to make 30 implant-retained mandibular molar restorations and divide equally into three groups: Group SRS: screw-retained restorations with SAH sealed; Group SRNS: screw-retained restorations with SAH not sealed; Group CR: cement-retained restorations. The following protocol was adopted to restore the SAH: the ceramic surface of the SAH was air-abraded with aluminum oxide; etched with 10% hydrofluoric acid; a silane coupling agent and a bonding agent were applied; cotton pellets were used as filling material and P-60 resin composite as restoring material. The cement-retained restorations were cemented with Rely-X U100. A metal rod with a spherical tip of 6.0 mm diameter was used to apply a vertical static load, simultaneously on the buccal and lingual incline cusps, at a crosshead speed of 0.5 mm/min until the fracture of the specimens. Data were analyzed using one-way ANOVA and Dunnet test (p<0.05) for multiples comparisons. The mode of failure was evaluated by a scanning electron microscopy (SEM). No significant difference between screw-retained restorations was found. The highest mean fracture resistance values were observed with CR group. Therefore, it was shown that SAH sealing did not influence the fracture resistance of the screw-retained restorations.

scholarly journals Laser assisted selective chemical metalization of Al2O3 films

2005 ◽  
Vol 3 (4) ◽  
pp. 668-673
Author(s):  
Emil Krumov ◽  
Dimitar Popov ◽  
Nikolay Starbov
Keyword(s):  
Thermal Evaporation ◽  
Chemical Deposition ◽  
Ceramic Surface ◽  
Ceramic System ◽  
X Ray ◽  
Deposited Metal ◽  
Metal Ceramic ◽  
Selective Chemical ◽  
Processing Steps ◽  
Al2o3 Films

AbstractThick aluminum oxide films are prepared on Al plates by anodizing. On the ceramic surface thus obtained a very thin Ag film is deposited via vacuum thermal evaporation. The Ag/Al2O3/Al samples prepared are irradiated by Nd:YAG laser through a suitable metal mask in order to remove the top metal film in the exposed areas. Thus, a negative silver image of the copied mask is obtained. Further, the samples are processed in Ni electroless chemical bath activated by the rest of silver. All processing steps are studied by scanning electron microscopy (SEM). EDS X-ray mapping is applied to study the final distribution of Al and Ni in the processed areas. In addition, the DC conductivity of the fabricated Ni wires obtained is measured. The proposed new method for selective chemical deposition of electroconductive Ni onto laser microstructured Ag/Al2O3/Al samples is simple, versatile and not restricted to the metal/ceramic system studied as well as to the electroless deposited metal.

High Temperature Chemical Interaction Between SiO2 Substrates and Ag-Cu Based Liquid Alloys in Vacuo

2006 ◽  
Vol 509 ◽  
pp. 117-122 ◽  
Author(s):  
Jorge López-Cuevas ◽  
Carlos A. Gutiérrez ◽  
Martin I. Pech-Canul ◽  
M. Castro-Román ◽  
Juan Carlos Rendón-Angeles
Keyword(s):  
Chemical Interaction ◽  
Liquid Alloys ◽  
Ceramic Surface ◽  
Metal Interface ◽  
Small Particles ◽  
Silver Alloys ◽  
Fused Quartz ◽  
Metal Ceramic ◽  
Quartz Substrates ◽  
Relative Thermodynamic Stability

The interfaces formed between vitreous or thermally devitrified fused quartz substrates and silver alloys after 90 min at 850 °C in vacuum have been characterized. Three silver alloys have been used: Cusil (Ag–28 wt % Cu), Cusil-ABA (Ag–35 wt % Cu–1.5 wt % Ti), and Incusil-ABA (Ag–27 wt % Cu–12 wt % In–2 wt % Ti). A non wetting condition is found for the Cusil alloy in both substrates. In contrast, the formation of Ti5Si3, Cu3Ti3O and Ti2O3, following the sequence SiO2 → Ti2O3 → Ti5Si3 → Cu3Ti3O, is observed at the metal/ceramic interface for the two titaniumcontaining alloys on both substrates. Ti2O3 is commonly found as small particles dispersed in a silver-rich matrix. During the experiments, the reaction product layers detach from the ceramic surface and float away from the ceramic/metal interface due to their relatively low density with respect to the liquid alloy. The formation of the phases detected at the ceramic/metal interface can be explained in terms of their relative thermodynamic stability.

Increased Resistance to Mechanical Shock of Metallic Materials by Metal-Ceramic Surface Coatings

2015 ◽  
Vol 638 ◽  
pp. 316-321
Author(s):  
Carmen Biniuc ◽  
Bogdan Istrate ◽  
Corneliu Munteanu ◽  
Luca Dorin
Keyword(s):  
Mechanical Properties ◽  
Surface Engineering ◽  
Microscopic Analysis ◽  
Scratch Test ◽  
Ceramic Coatings ◽  
Experimental Results ◽  
Ceramic Surface ◽  
Mechanical Shock ◽  
Metal Powders ◽  
Metal Ceramic

In the last time, material engineering in lately developed the design and processing technology of materials in well-defined goals. Thus, they designed and achieved the metal alloys for use in strong fields required mechanical shock using methods of surface engineering. In this direction, we have developed very superficial deposition techniques by thermal spray of ceramic and metal powders, both for hard coating and to protect surfaces in refractory environments. In a controlled manner, can form new structures, which leads to an improvement in the tribological properties of the coatings obtained. In this paper are described experimental results obtained after the tests of resistance to mechanical shock testing of metal-ceramic coatings on forged titanium support. We analyzed the behavior of thermal deposited layers of ZrO2 stabilized with 8% Y2O3 and Al2O3 after applying mechanical shock test and scratch test. These materials were analyzed in terms of structural, of mechanical properties and adhesion of the surface layers using electron microscopy, X-ray diffraction, Charpy device, CETR UMT-2 tribometer. The results showed that the materials investigated have a stratified columnar structure, shows lamellar and intra - lamellar cracks and pores formed between neighbor "splat's". From microscopic analysis, after these tests, it was observed that the thermal deposited layers were not separated and there was a fingerprint on their surface. The experimental results show that the new structures obtained presents much better mechanical properties compared to the material, forged titanium, no deposit.

Influence of the Metal/Ceramic Interface Characteristics on Conductivity Measurements of Na-β" Alumina by Impedance Spectroscopy

1992 ◽  
Vol 293 ◽  
Author(s):  
M. Schreiber ◽  
E. Butchereit ◽  
C. Lutz
Keyword(s):  
Impedance Spectroscopy ◽  
Ceramic Surface ◽  
Analysis Techniques ◽  
Surface Analysis Techniques ◽  
Conducting Materials ◽  
Interface Characteristics ◽  
Metal Ceramic ◽  
Before And After ◽  
Standard Quality

AbstractThe quality of the metal/ceramic interface of solid ionically conducting materials is an important when undertaking impedance spectroscopy measurements. One major concern is the contact area between the metal and the ceramic. This work focussed on the treatment of the ceramic to the metal application by utilizing a standard quality Na-β" alumina. Next, a number of different metals were applied to the ceramic surface by different techniques, i.e. sputtering and evaporation, to serve as blocking electrodes in impedance spectroscopy measurements. The impedance spectroscopy measurements were carried out at temperatures from 30 - 300°C over a frequency range from 1 to 5 ×105 Hertz. The results are discussed in terms of the various parameters of impedance plots. Surface analysis techniques were applied to investigate the metal/ceramic interface before and after impedance spectroscopy measurements.

High Temperature Chemical Interaction Between SSiC Substrates and Ag-Cu Based Liquid Alloys in Vacuo

2006 ◽  
Vol 509 ◽  
pp. 111-116 ◽  
Author(s):  
Jorge López-Cuevas ◽  
Juan Carlos Rendón-Angeles ◽  
J.L. Rodríguez-Galicia ◽  
M. Herrera-Trejo ◽  
J. Méndez-Nonell
Keyword(s):  
Electron Microscopy ◽  
Chemical Interaction ◽  
Silica Film ◽  
Liquid Alloys ◽  
Ceramic Surface ◽  
X Ray Diffraction ◽  
Metal Interface ◽  
X Ray ◽  
Metal Ceramic ◽  
Scanning Electron

The interfaces formed at 850 °C under vacuum between polished or oxidized substrates of pressureless sintered α-SiC (SSiC) and Cusil, Cusil-ABA and Incusil-ABA brazing alloys have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. No chemical interaction is observed for Cusil on both SSiC substrates. In contrast, the Ti contained in the Cusil-ABA and Incusil-ABA alloys promotes the occurrence of chemical reactions at the metal/ceramic interface with both SSiC substrates. The formation of TiC and Ti5Si3 is observed for Cusil-ABA and Incusil-ABA on untreated SSiC, following the sequence SiC → TiC → Ti5Si3 at the metal/ceramic interface. The formation of Ti5Si3 and Cu3Ti3O, following the sequence SiC → Ti5Si3 → Cu3Ti3O, is observed for both Ti-containing alloys on pre-oxidized SSiC. During the wetting experiments, Ti5Si3 and Cu3Ti3O detach from the ceramic surface, floating away from the ceramic/metal interface into the liquid alloy, where the latter phase partially dissolves. It is concluded that for both Ti-containing alloys in contact with pre-oxidized SSiC, the Ti remaining after the reaction with the silica film is insufficient to decrease the contact angle to the values observed for untreated SSiC or to produce a strong metal/ceramic joint.

Influence of Interfacial Temperature on the Adhesion Properties of Plasma-Sprayed Metal-Ceramic Coatings

1998 ◽  
Author(s):  
C.R.C. Lima ◽  
R.D.E. Trevisan
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Ceramic Coatings ◽  
Industrial Applications ◽  
Thermal Barrier ◽  
Adhesion Properties ◽  
Barrier Coating ◽  
Metal Ceramic ◽  
Interfacial Temperature ◽  
Plasma Sprayed

Abstract Metal-ceramic coatings have been widely used for industrial applications, mainly in the thermal barrier coating technology (TBC). Plasma spraying is the common manufacturing process of TBC's. Conventional thermal barrier coatings consist of a metallic bond coat layer and an insulating ceramic overlay. Graded coatings or functionally gradient coatings have also been applied in order to solve the problems associated with the early spallation of plasma-sprayed conventional TBCs. Temperatures and gradients during plasma spraying have and important influence on the coating quality, specially the temperature of the particles just hitting the substrate surface. When applying so distinct materials like metals and ceramics this fact has an increased importance. In this work metal-ceramic coatings have been applied on metallic substrates. The interfacial temperature measurements were performed by optical pyrometry. The substrate temperature was measured by thermocouples. The adhesion of the coatings was determined by standard ASTM tests and correlated with the measured temperatures. In a general way, results show that the coatings with lower adhesion values were that with lower interfacial measured temperatures.

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