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Fracture indentation was applied to estimate the fracture toughness of AISI 1018 borided steels. The Fe2B hard layers were formed using the powder-pack boriding process for two temperatures with 4 and 8 h of exposure times. The fracture toughness of the iron boride layer of the AISI 1018 borided steels was estimated using a Vickers microindentation induced-fracture testing at distances of 15 and 30 m from the surface, applying four loads (0.49, 0.98, 1.96 and 2.9 N). The microcracks generated at the corners of the Vickers microindentation were considered as experimental parameters, which are introduced in a Palmqvist crack model to determine their corresponding fracture toughness KC. As a result, the experimental parameters, such as exposure time and boriding temperature are compared with the resulting fracture toughness of the borided phase.

This study evaluates the adhesion of boride layers on the surface steels of AISI 4140, 8620, W2 and H13 by standard VDI 3198 [1], the surface hardened was carry out by the technique of power pack boriding at the temperatures of 1273 K, with time exposition of 6 and 8 h. The presence of boride phases was determinate by X-ray diffraction (XRD) analysis. A Rockwell C indentation tester was applied on the surface steels boriding, this impact test determines qualitatively the adhesion on layer/substrate indentation print and Vicker microhardnes was evaluate a load of 2.9 N on phase FeB and Fe2B, the steels have scale delamination H1 to H6.

This paper studies the formation of boride layers on substrate injector combustion AISI 304 per nozzle surface treatment in addition the formation of hard layers and FeB type Fe2B were obtained in a temperature range of 1223 and 1273 K with exposure times of 1/2, 1, 3 and 5 h. The study consisted boride type layer formed on the surface and the characterization of the boride layer were evaluated by the method by analysis of X-ray diffraction (XRD), the distribution of the alloying elements were detected by spectrometry energy Dispersive (EDS) inside the surface, the evaluation of adhesion of the layers was determined by the technique Rockwell-C hardness was also evaluated and the Young's modulus of the layer by the nanoindentation technique with the load of 200 mN. Finally this study hardening fuel injector; is desired increase its useful life.

The characterization and fracture toughness with hard coatings formed at the surface of gray cast irons class 30 is evaluated in the present study. The formation of hard coatings was obtained out means of the pack boriding process; the treatment was carried out at temperatures of 1173 and 1223 K during 6 hours. The layers were evaluated by the techniques of X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and microindentation across the thickness of the iron boride layer. Three-point bending tests are carried out to examine the fracture toughness of gray cast irons boriding according to the ASTM 399 standard. Consequently, the stress intensity factor was evaluated by means of the finite element method (FEM) using the package ANSYS 11. 0 creating a two-dimensional model with elements of singularity around the tip crack. The results were compared with the experiments and have been found to be in good correlation.