The development of dry self-lubricating materials is directly linked to the rising requirements of performance. Iron and steel are the most used metals around the world and molybdenum disulfide (MoS2) one of the most used solid lubricant. Therefore it is expected that one might try to develop self-lubricating steels containing MoS2, however MoS2 reacts with steel matrices during sintering. This work has focused on the study of these reactions; temperatures at which this occurs; the influence of particle sizes and MoS2 content and also MoS2 influence during processing and in the parts properties. The results showed that the reaction occurs at lower temperatures than the predicted and the products are iron-molybdenum and iron sulfides. The sintering studies revealed that MoS2 enhances sintering and the particle size and MoS2 content directly influenced the morphology and chemical composition of the resulting phases.

This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermosprayed aluminum (3'year evaluation) and conventional Al/Zn/In anocies in an epoxy-painted steel bracelet (IZ-year evaluation)), indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermosprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials (<-1100 mV vs. CU/CUSO4) they supply to the reinforcement could lead to hydrogen embrittlement.

This paper presents a novel way to obtain reinforced pores by the dissociation of mixed carbides during sintering. Porous materials have a wide range of applications such as dampeners, light structures, etc. But usually pores act as points of stress concentration and crack nucleation, harming the mechanical properties of these materials. Methods have been developed to control the shape and size of pores but, until now, there are no techniques that allow reinforcing the material around the pores. To address this, steels were prepared by adding 1, 3 and 5 wt.% of Mo1.5Cr0.5C mixed carbide particles to a iron matrix by metal injection moulding. The results showed that during sintering, the dissociation of the carbide followed by the dissolution of the elements in the matrix generated rounded secondary pores with a reinforced vicinity, which increased the mechanical strength of the materials. The presence of rounded pores encircled by an enriched vicinity can allow the production of porous materials with exceptional fatigue strength and fracture toughness.

Sintered iron samples were produced using different pressing loads, resulting in different residual porosities of approximately 14%, 18%, 22% and 30%. Iron-matrix composites, containing 2.5, 5.0, 7.5 and 10.0 %vol. of dispersed hexagonal boron nitride (hBN) particles, were also produced. The influence of these parameters on the amplitude-dependent damping capacity was assessed using a dynamic-mechanical analyser. The simultaneous effect on mechanical strength was assessed through a tensile test. The microstructure was analysed with optical and electronic microscopy and quantitatively evaluated through a digital image analysis. It was verified that the increase of porosity did not lead to a representative increase in the damping capacity of sintered iron. On the other hand, higher hBN content leads to a higher damping capacity due to the introduction of robust new damping mechanisms. However, hBN reservoirs, which are bigger and more elongated than the pores, are more detrimental to mechanical strength.