Effect Of SiC Addition Research Articles

Effect of SiC Addition on Sintering Behavior and Properties of Indium Tin Oxide

The sintering behavior of ITO ceramics with the addition of fine and coarse SiC was studied. SiC addition promoted the densification of ITO during early stage sintering compared to pure ITO. On the other hand, the addition of SiC resulted in the development of numerous pores in the microstructures due to the oxidation of SiC during sintering. In particular, swelling of the samples, which lead to an expansion of the sample, was observed when 1.0 wt% of fine SiC was added. Fine SiC particles are believed oxidize faster than coarse SiC particles, and SiC oxidation during sintering resulted in a low density and high porosity regardless of the SiC particle size.

The effect of SiC addition on the crystallization kinetics of atmospheric plasma–sprayed basalt-based coatings

The crystallisation kinetics of the conversion of a glass coating layer made from a mixture of natural basalt volcanic rock and SiC into glass-ceramic have been investigated. The process depends on the crystallisation temperature, time and amount of the SiC added. Coating powders were prepared from pure basalt and from basalt containing 10–50wt% SiC. The powders were coated by an atmospheric plasma spray technique on the pre-coated AISI 1040 steel substrate with Ni–Al. The coating layer was vitrified by sudden cooling. The amorphous structure of the coatings was verified by X-ray diffraction (XRD) analysis. To obtain glass-ceramic, coatings were subjected to crystallisation heat treatment in an argon atmosphere. Crystallisation heat treatment temperatures of 800°C, 900°C and 1000°C were chosen by using DTA. After the heat treatment process, augite, ferrian-diopsite, diopside, albite, andesine, and moissonite phases formed in the coating layer and were verified by XRD analysis. The crystallisation activation energies were determined to be between 323.4kJ/mol and 253.2kJ/mol, depending on SiC addition. The crystallisation activation energies decreased with increasing amounts of SiC addition. The Avrami parameters of the crystallisation process varied between 1.60 and 3.33, which indicates that internal crystallisation dominated for all of the compositions.

Effects of SiC Addition on the Properties of MgO-Based Castables

The effects of SiC addition on physical properties and slag resistance of MgO-based castables were investigated using magnesia as the main raw and silica micropowder as binder. The result revealed that with increasing SiC addition, dried strength decreased, medium and high temperature strength first increased and then decreased and reached a maximum at 3% SiC addition. The hot modulus of rupture (HMOR) of the materials maximized at 3% SiC addition. The slag penetration resistance of the castables was improved while resistance to slag attack was deteriorated with the increase in SiC addition. The materials exhibited optimum slag resistance at 3% SiC additions.

On the crystallite size refinement of ZrB 2 by high-energy ball-milling in the presence of SiC

The effect of SiC addition (5, 17.5, and 30 vol.%) on the high-energy ball-milling (HEBM) behaviour of ZrB 2 is investigated. It was found that the presence of SiC during HEBM did not alter ZrB 2 refinement mechanism of repeated brittle fracture followed by cold-welding, thereby leading to the formation of agglomerates consisting of primary nano-particles. SiC did, however, slow down the kinetics of crystallite size refinement and promoted the formation of finer agglomerates. Both of these phenomena became more pronounced with increasing SiC content in the ZrB 2 + SiC powder mixtures, and they were attributed to the energy dissipation effect of the nanocrystalline SiC particles during HEBM of the ZrB 2 + SiC powder mixture. This study offers the first evidence that the addition of harder materials to softer materials can slow down the refinement of crystallite sizes, and thus provides a new mechanism to control crystallite sizes during HEBM. The simultaneous attainment of nano-particles of ZrB 2 and SiC, reduced agglomerate sizes, and homogeneous SiC dispersion at the nanometre scale may have important implications for the ultra-high-temperature ceramic community, as it simplifies the processing route and is likely to facilitate the sintering of ZrB 2–SiC composites.

The effect of SiC additives on fretting wear of electroplated NiP coatings

The present work studies the effect of reinforcing additives of submicron-size silicon carbide and thermal treatment on fretting wear of nickel-phosphorus (NiP) electroplated coatings. The tests are conducted under a 500-μm shear of the friction contact. The tribotests show that all coatings under study undergo abrasive-oxidative wear. Thermal treatment is found to reduce the friction coefficient and wear rate of the coatings under fretting, whereas the increased content of the SiC additive leads to increased friction coefficient and wear rate. The annealed NiP coatings have a lower wear rate compared to the composite NiP-SiC coatings.

Effects of SiC Nanodispersion on the Thermoelectric Properties of p-Type and n-Type Bi2Te3-Based Alloys

Polycrystalline p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.7Se0.3 thermoelectric (TE) alloys containing a small amount (vol.% ≤5) of SiC nanoparticles were fabricated by mechanical alloying and spark plasma sintering. It was revealed that the effects of SiC addition on TE properties can be different between p-type and n-type Bi2Te3-based alloys. SiC addition slightly increased the power factor of the p-type materials by decreasing both the electrical resistivity (ρ) and Seebeck coefficient (α), but decreased the power factor of n-type materials by increasing both ρ and α. Regardless of the conductivity type, the thermal conductivity was reduced by dispersing SiC nanoparticles in the Bi2Te3-based alloy matrix. As a result, a small amount (0.1 vol.%) of SiC addition increased the maximum dimensionless figure of merit (ZT max) of the p-type Bi0.5Sb1.5Te3 alloys from 0.88 for the SiC-free sample to 0.97 at 323 K, though no improvement in TE performance was obtained in the case of n-type Bi2Te2.7Se0.3 alloys. Importantly, the SiC-dispersed alloys showed better mechanical properties, which can improve material machinability and device reliability.

Structural characterization of plasma sprayed basalt–SiC glass–ceramic coatings

In the present study, the effect of SiC addition on properties of basalt base glass–ceramic coating was investigated. SiC reinforced glass–ceramic coating was realized by atmospheric air plasma spray coating technique on AISI 1040 steel pre-coated with Ni+5wt.%Al bond coat. Composite powder mixture consisted of 10%, 20% and 30% SiC by weight were used for coating treatment. Controlled heat treatment for crystallization was realized on pre-coated samples in argon atmosphere at 800°C, 900°C and 1000°C which determined by differential thermal analysis for 1–4h in order to obtain to the glass–ceramic structure. Microstructural examination showed that the coating performed by plasma spray coating treatment and crystallized was crack free, homogeneous in macro-scale and good bonded. The hardness of the coated samples changed between 666±27 and 873±32HV0.01 depending on SiC addition and crystallization temperature. The more the SiC addition and the higher the treatment temperature, the harder the basalt base SiC reinforced glass–ceramic coating became. X-ray diffraction analysis showed that the coatings include augeite [(CaFeMg)–SiO3], diopside [Ca(Mg0.15Fe0.85)(SiO3)2], albite [(Na,Ca)Al(Si,Al)3O8], andesine [Na0.499Ca0.492(Al1.488Si2.506O8] and moissanite (SiC) phases. EDX analyses support the X-ray diffraction analysis.

Effects of SiC addition on the structure and properties of reticulated porous mullite ceramics

Reticulated porous mullite ceramics (mullite RPCs) were produced by the polymer replica method using alpha alumina and kaolin to form in situ mullite. Up to 30% particulate silicon carbide (SiCp) was added to ceramic mixtures to explore its effect on the structure and properties of the sintered products. The ceramic slurry was coated onto polyurethane sponge using preset roller method, then recoating was applied by the spray coating technique. The strength of the mullite RPCs was found to depend greatly on the phase composition of the structures and on the amount of SiCp addition.

Aluminium‐silicon alloy and its composites reinforces by silicon carbide particles

PurposeThe purpose of this paper is to investigate the effect of SiC addition up to 60 percent SiC on the mechanical properties and thermal expansion of Al‐7vol.% Si/SiC composites.Design/methodology/approachComposite specimens containing 7, 15, 30, 45 and 60 vol.% SiCp are fabricated by pressureless infiltration technique. The obtained metal‐matrix composites (MMCs) then are characterized for density, porosity, microhardness, ductility, and coefficients of thermal expansion (CTE).FindingsThe results show that the composite specimens have very low‐porosity volumes. Moreover, it is found that silicon carbide particles are distributed uniformly in the matrix. Both porosity and mean linear CTE of the composites decreases with silicon carbide volume fraction. However, higher amount of SiCp reinforcement content tends to increase density, microhardness and improve ductility.Originality/valueThe processing employed in this paper would enable realization of electronic packages made out of Al‐Si/SiCp MMCs.

Strengthening mechanism of SiC-particulate reinforced Sn–3.7Ag–0.9Zn lead-free solder

Mechanically mixing was adopted to prepare SiC-particulate reinforced Sn–3.7Ag–0.9Zn composite solders and the effects of SiC addition on the solidification behavior, melting behavior and the corresponding microhardness of air-cooled composite solders were explored. It is found that the addition of SiC particles into the Sn–3.7Ag–0.9Zn alloy melt prompts the formation of primary β-Sn phase in the solidified structure. For the SiC particles serve as additional nucleation sites for the formation of primary β-Sn phase, the sizes of both the β-Sn dendrites and the intermetallic compounds (IMCs) decrease gradually with the SiC particles increasing. The hard SiC particles and refined β-Sn dendrites and IMCs could obstruct the dislocation slipping and thus lead to a strong strengthening effect in the composite solder.

$J_{\rm c}$ Anisotropy and Pinning Behaviors of the In-Situ $\hbox{MgB}_{2}$ Wires With/Without SiC Addition

In an attempt to understand the effects of SiC addition on the pinning behavior for the in-situ PIT MgB2 tape wire, field and temperature dependencies on critical current density, Jc and the pinning force were studied by considering applied magnetic field direction for the rectangular-shaped wire. As a result, it was clarified that the SiC-doped wire has the equiaxial pinning center and the un-doped wire has the inequi-axial pining center. Taking the pinning scaling law into account, it is found that the SiC-doped MgB2 wire has two kinds of the pinning center and the dominant pinning center changes with temperature, that is, the pinning centers are the grain boundary and the precipitates at high and low temperatures, respectively. The un-doped MgB2 wire is assumed to have anisotropy of the pinning mechanism.

Preparation and Flame Ablation/Oxidation Behavior of ZrB<sub>2</sub>/SiC Ultra-High Temperature Ceramic Composites

ZrB2/SiC ceramic composites reinforced by nano-SiC whiskers and SiC particles have been prepared by hot-pressing at 1950°C for 1hr under 20 MPa pressure in flow argon atmosphere. Effects of SiC addition on microstructure, mechanical properties and thermal ablation/oxidation behavior of ZrB2/SiC composites were investigated. The results showed that the addition of SiC effectively improved the densification of ZrB2/SiC composites and almost full dense ZrB2/SiC composites were obtained when the amount of SiC increased up to 20 vol%. Flexural strength and fracture toughness of the ZrB2/SiC composites were also enhanced; the maximum strength and toughness reached 600 MPa and 8.81 MPa·m1/2 at SiC additions of 20 vol % and 30 vol%, respectively. The composites possessed good resistance to flame ablation and could keep the whole shape without distinct peeling or cracking after flame ablation by oxyacetylene flame for 3 mins. The more SiC added, the better resistance to flame ablation the composites displayed.

Particle -Reinforced SiAlONs for Cutting Tools

CeramTec AG is a well-known manufacturer of cutting tool materials, especially for inserts based on silicon nitride. Some years ago it started the production of alpha/beta-SiAlONs because of their superior properties. Due to strong competition in the cutting tool business there is a constant need for further development of the cutting tool materials. One possibility to increase wear resistanceand life time of cutting tools is to increase the hardness and maintaining the good toughness at the same time. This can be done by adding hard particles like e.g. SiC to an alpha/beta- SiAlON. In 2003 an improved grade had been presented: a SiC-reinforced alpha/beta-SiAlON. This composite material shows a significantly reduced wear during machining of cast iron. The effect of SiC-addition on mechanical properties is discussed.

Effects of SiC addition on formation of Ti3SiC2 by self-propagating high-temperature synthesis

Formation of Ti 3 SiC 2 was conducted by self-propagating high-temperature synthesis (SHS) from both the elemental powder compact of Ti:Si:C = 3:1:2 and the SiC-containing sample with SiC content ranging from 4.3 to 20 mol%. The effect of SiC addition was studied on combustion characteristics and the degree of phase conversion. In addition, two forms of the elemental carbon, carbon black and graphite, were employed in the starting mixture and their influence was also explored. The synthesis reaction of the powder compact is characterized by a distinct combustion front propagating along the sample in a self-sustaining manner. Due to the significantly higher thermal conductivity of graphite, lower reaction temperatures and combustion wave velocities were observed in the samples with graphite than those using carbon black. For both types of the samples, the addition of SiC reduced the reaction temperature and thus decreased the flame-front propagation velocity. As a result of the increase of reaction time, the degree of phase conversion was enhanced by the addition of SiC and by the use of graphite as the carbon source. For all as-synthesized products, the XRD analysis identifies formation of Ti 3 SiC 2 along with a second phase TiC and a small amount of Ti 5 Si 3 . The resulting Ti 3 SiC 2 is typically elongated grains with a closely packed pattern. Based upon the XRD profile, the products with Ti 3 SiC 2 contents of 71.5 and 82.5 vol.% were obtained from the elemental powder compacts with carbon black and graphite, respectively. For both types of the reactant compacts containing 20 mol% of SiC, an optimum yield about 85 vol.% of Ti 3 SiC 2 was achieved.

Pinning properties in pure and SiC doped MgB2 bulk obtained by reactive Mg liquid infiltration technique

The effects of SiC additions on pinning properties of MgB2 bulk samples, obtained by reactive Mg liquid infiltration (RLI) in Boron powders preforms have been analysed by means of electric transport measurements at different applied magnetic fields. For doped and undoped systems the E vs. J characteristics as well as the pinning energy dependence as a function of the current density has been evaluated and analysed in the framework of thermal creep models. The doping-induced pinning centres, very effective in the pinning property improvements, turned out to be of similar nature than those of the undoped sample and can be mostly attributed to SiC reactive insertions inside the MgB2 grains with an increase of lattice disorder induced by the relative reaction products.

Effect of ceramic particle addition on the foaming behavior, cell structure and mechanical properties of P/M AlSi7 foam

The effects of SiC addition on the foaming behavior and compressive properties of AlSi7 metal foams were studied. Elemental powders of Al, Si, SiC and TiH 2 were mixed, hot compacted and foamed at temperatures between 750 and 810 °C. The role of SiC volume fraction up to 10 vol.% and its particle size (3, 8 and 16 μm) was investigated. It was found that the foaming behavior of AlSi7 alloy, i.e. the maximum foam expansion and its stability, depends on the size and volume fraction of SiC particles. Increasing the amount of the ceramic particles and/or decreasing the particle size leads to less melt drainage whilst the cell structure becomes non-uniform. This is attributed to the effect of the ceramic particles on the viscosity of the aluminum melt and the cell wall thinning rate. Here, it was noticed that the effect of SiC addition is closely related to the temperature used for the foaming process. Also, a slight degradation in the mechanical properties under compressive load was observed. Better foamability with improved stability and proper mechanical properties were obtained in AlSi7–3 vol.% SiC (3 μm) precursor foamed at 810 °C.

Effect of SiC addition and running-in-wear on the sliding wear behaviour of Al–Zn–Mg aluminium alloy

Sliding wear behaviour of Al–Zn–Mg alloy and Al–Zn–Mg–SiC particle composite was studied under varying applied load. Effects of running-in-wear on sliding wear characteristics of the alloy and composite was studied giving emphasis on the parameters such as coefficient of friction, rise in temperature, wear rate and seizure pressure. The seizure pressure of composite was noted to be significantly higher than that of the alloy and is increased further due to running-in-wear prior to the test. The running-in-wear also improved the wear resistance and seizure pressure of the alloy, whereas both the coefficient of friction and temperature rise are reduced due to running-in-wear. However, the level of improvement in seizure pressure due to running-in-wear is relatively less in composite (22%) as compared to that in alloy (40%). These facts have been discussed on the basis of nature of worn surface produced after running-in-wear. The worn surface was studied in detailed through scanning electron microscopy, EDX analysis and X-ray diffraction measurement. Transfer of counter surface material, the formation and stability of mechanically mixed layer (MML) in the investigated materials were assessed indirectly through these analyses. The MML is noted to be more stable in running-in-wear samples as compared to the fresh samples both in alloy and composites.

Effect of SiC Additions on the Spontaneous Crystallization and Properties of Diamond

The effect of silicon carbide additions on the spontaneous crystallization and properties of diamond is studied. The results demonstrate that increasing the SiC content of the growth charge increases the crystal yield (reduces the concentration of paramagnetic centers) and the fraction of small crystals and influences the melt composition.

Carbon and carbon-containing refractory materials for blast-furnaces at the Chelyabinsk Electrode Plant Joint-Stock Co.

The effect of SiC additives and the granular composition on porosity, abrasive resistance, and endurance of carbon refractory blocks used in the blast-furnace steel-making technology. The use of microporous refractory blocks makes it possible to extend the blast-furnace production campaign by several years. The high efficiency of low heat-conducting cold-rammed mixes and a carbon-containing concentrate (available from ChEP JSC) is discussed.

Mechanical Properties of Sputter‐Deposited Titanium‐Silicon‐Carbon Films

The effect of SiC additions on the mechanical properties of TiC films was investigated. Ti‐Si‐C films with varying SiC content were deposited using dual‐cathode radio‐frequency magnetron sputtering. The nanoindentation hardness of these films increased with SiC content to a maximum of 20–22 GPa for films in the range of 15–30 at.% SiC. The elastic modulus was also measured, and the hardness to modulus ratio (H/E) increased with SiC content, indicating that hardness increases were due to microstructural effects. The residual stress was measured in several films, but was low in magnitude, indicating that hardness measurements were not influenced by residual stress. TEM examination of several films revealed that the SiC additions altered the film microstructure in a manner that could account for the observed hardness increases.