This paper presents the possibility of syntactic foam production by pressure infiltration technology. Syntactic foams have low density and relatively high strength. Therefore they can be the material of many important parts in automotive technology or in aviation. The parameters of infiltration were studied and physical and mechanical investigations were performed. Microscopic investigations showed almost perfect infiltration at the applied infiltration pressure. The densities of the foams were significantly decreased. Low density ensures good specific properties and economical energy consuming in the case of moving the parts. Syntactic foams showed a plateau region in their upsetting diagrams and absorbed a high energy during upsetting. The effect of aspect ratio was also investigated. Specimens with higher aspect ratios showed lower peak stress, lower plateau level and higher modulus of elasticity.Keywords metal matrix composite · pressure infiltration · metallic foam · syntactic foam · ceramic microballoon · hollow sphere.

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Several process variants of plasma nitriding can be distinguished depending on the location of the voltage introduction. The aim of this study is to compare three different variants of plasma nitriding (DC plasma nitriding, active screen plasma nitriding, and active screening process with bias voltage application) extended by the study of the coverage of active screen on C45E unalloyed steel, using two different N 2-H 2 gas mixtures. The thickness of the compound layer was measured using a scanning electron microscope, the phase analysis was performed by an x-ray diffractometer, and the nitrogen contents were analyzed by glow discharge optical electron spectroscopy. The results showed that the layer thickness and the surface hardness were higher by using active screen-biased plasma nitriding with high N 2 content gas mixture. Besides, the lid of the active screen did not influence significantly the chemical composition of the compound layer.