Mario Caccia

Montana Tech of the University of Montana | Montana Tech · Metallurgical & Materials Engineering

Compact heat exchangers have gained increased attention in recent years, particularly in demanding applications where high temperatures, high pressures, and/or high power densities are required. For decades, the heat exchanger (HX) community believes that flow maldistribution is a key factor for HX effectiveness, that is, reducing the degree of flo...

Residual stress, when superimposed with in-service loading, can significantly reduce the lifetime and performance of a component. Ceramic-metal composites are susceptible to residual stresses due to the thermal expansion mismatch of the ceramic and metallic phases. The WC-Cu composite explored in the present study provides a promising combination o...

The fracture behavior of a melt-infiltration-processed SiC/Si composite, used to mimic the matrices of industrial fiber-reinforced ceramic composites, was examined in different atmospheres and temperatures. Specimens tested in four-point bending at 900 °C in oxygen-gettered argon, dry air, or steam-rich atmospheres exhibited higher average fracture...

Purpose: To investigate and compare the effects of the two widely used regenerative endodontics medicaments: Triple antibiotic paste (ciprofloxacine-metronidazole-clindamycin) and calcium hydroxide on the microhardness and degradation of human root dentin. Methods: Following ethical approval and subject consent to use teeth in this research stud...

Compact heat exchangers (HXs) have gained attention in recent years in various fields such as solar and nuclear power generation, oil and gas, and refrigeration due to their low cost, high power density, and robustness in high-pressure and/or high-temperature environments. However, the large difference between a compact HX's overall dimensions (~ m...

To increase the power cycle efficiency and lower the levelized cost of electricity (LCOE) of concentrated solar power (CSP) plants, printed circuit heat exchangers (PCHEs) capable of operating above 700 °C with molten chloride salt and a sCO2-based fluid are needed. In this paper, the design of a high-pressure, high-temperature, 2 MW PCHE comprised...

The heat-to-electricity conversion efficiency of concentrated solar power plants may be enhanced, for lower cost electricity generation, by using high-temperature (750oC) supercritical CO2 as a working fluid to drive the turbines in these plants. Unfortunately, such operation has been inhibited by the reduction in thermomechanical performance at >5...

Complex-shaped, finely-featured, ultra-high-melting ZrC/W composite structures were produced by coupling, for the first time, three-dimensional (3-D) ink-extrusion printing with shape/size-preserving reactive melt infiltration (the Displacive Compensation of Porosity, DCP, process). Inks containing sub-micron WC powders were printed at ambient temp...

Hot-pressed Al2O3/Cr and Ti2O3/Cr composites were exposed to synthetic air or CO2 at 750 °C. The Al2O3/Cr composites formed external Cr2O3 scales, and exhibited slow parabolic oxidation kinetics, in both gases. The Cr2O3 scales formed in CO2 possessed finer grains, and thickened at a faster rate, than Cr2O3 scales formed in air. The Ti2O3/Cr compos...

Porous SiC with a hierarchical mesoporous structure is a promising material for high‐performance catalytic systems because of its high thermal conductivity, high chemical inertness at high temperature, and oxidation resistance. Attempts to produce high‐surface area hierarchical SiC have typically been made by using porous carbon as a template and r...

Synthesis of SiC-based composites using microwave(MW)-assisted reactive infiltration is a promising way to obtain these materials at lower costs due to a reduction in processing time and energy consumption. Hot spots are likely to form during this process due to the different dielectric properties of the various phases and the exothermic nature of...

The manufacture of SiC-based composites is quite widespread, and currently different methods are employed to produce them. The most efficient method, taking into account the cost/performance ratio, is reactive melt infiltration. It consists in infiltrating liquid silicon into a porous preform that must contain carbon, so that SiC is produced during...

The manufacture of SiC-based composites is quite widespread, and currently different methods are employed for to produce them. The most efficient method, taking into account the cost/performance ratio, is reactive melt infiltration. It consists in infiltrating liquid silicon into a porous preform that must contain carbon, so that SiC is produced du...

The efficiency of generating electricity from heat using concentrated solar power plants (which use mirrors or lenses to concentrate sunlight in order to drive heat engines, usually involving turbines) may be appreciably increased by operating with higher turbine inlet temperatures, but this would require improved heat exchanger materials. By opera...

The efficiency of generating electricity from heat using concentrated solar power plants (which use mirrors or lenses to concentrate sunlight in order to drive heat engines, usually involving turbines) may be appreciably increased by operating with higher turbine inlet temperatures, but this would require improved heat exchanger materials. By opera...

Carbon monolithic adsorbents exhibiting a hierarchical pore structure are produced via a synthesis route based on the stabilization of liquid foams followed by a carbonization step. The macro-microporous structure is achieved by the incorporation of microporous, biomass-derived activated carbon particles in the liquid foam enclosed by a cationic su...

Integration of graphene into electronic circuits through its joining with conventional metal electrodes (i.e. gold) appears to be one of the main technological challenges nowadays. To gain insight into this junction, we have studied the physicochemical interactions between SiC-supported graphene and a drop of molten gold. Using appropriate high tem...

Advanced ceramics such as silicon carbide (SiC) have shown an excellent performance under impact loading, and given their low density, they have attracted attention to be used in personal armor as well as in vehicles. Sintered SiC presents, nevertheless, an elevated cost which is a direct consequence of the severe temperature and pressure condition...

This chapter discusses the impact of vacuum on microstructure and mechanical properties of silicon carbide generated by reactive infiltration. SiC is a ceramic material that has undergone a major expansion of its use in recent years especially in the aerospace and nuclear industry for its excellent properties. Infiltration of the samples was carrie...

This chapter discusses how SiC-ZrSi2 composites were fabricated by reactive melt infiltration of Si-Zr alloys into porous C/SiC preforms in an experiment. The resulting materials were SiC/ZrSi2 composites, in which remaining silicon was considerably reduced by formation of ZrSi2. The composite materials obtained showed an excellent thermal compatib...

Remaining silicon in SiC-based materials produced via reactive infiltration limits their use in high temperature applications due to the poor mechanical properties of silicon: low fracture toughness, extreme fragility and creep phenomena above 1000 degrees C. In this paper SiC-FeSi2 composites are fabricated by reactive infiltration of Si-Fe alloys...

The knowledge of thermophysical properties of liquid Co-Si alloys is a key requirement for manufacturing of composite materials by infiltration method. Despite this need, the experimental and predicted property data of the Co-Si system are scarce and often inconsistent between the various sources. In the present work the mixing behaviour of Co-Si m...

Remaining silicon in SiC-based materials produced via reactive infiltration limits their use in high-temperature applications due to the poor mechanical properties of silicon: low fracture toughness, extreme fragility and creep phenomena above 1000 °C. In this paper SiC–FeSi2 composites are fabricated by reactive infiltration of Si–Fe alloys into p...

Among manufacture techniques for SiC ceramics, reactive infiltration has proven to be the most efficient. However, materials manufactured with this technique present minimum 10% of unreacted silicon. Si hinders the performance of the material. The replacement of Si with a MexSiy can improve the performance of the composite. Since Me–Si alloys wet c...

It is well known that there are several processes to manufacture composite materials, a large part of which consist in the infiltration of a liquid (matrix) through a porous medium (reinforcement). To perform these processes, both thermodynamics (wet‐ ting) and kinetics (Navier-Stokes) must be considered if a good quality composite material is soug...

Silicon Carbide (SiC) is one of the most important advanced ceramic, due to its unique set of electrical, optical, thermal and mechanical properties. The main barrier nowadays to wider the use of SiC is its manufacturing process, which requires very high temperatures (above 2000 °C) and pressures (> 100 MPa), is time consuming and allows a non well...

The use of oak sawdust as carbon precursor for SiC manufacture via reactive infiltration was studied. The effect of oak sawdust pressing parameters, temperature and pressure, on the final SiC's properties was studied. Final product's quality was evaluated through density measurement, and microstructure and pore size distribution variations were cha...

Diamond/metal composites are very attractive materials for electronics because their excellent thermal properties make them suitable for use as heat sink elements in multifunctional electronic packaging systems. To enlarge the potential applications of these composites, current efforts are mainly focused on investigating different ways to improve t...