Name: FILIPE DONDONI RAMOS
Publication date: 16/06/2026
Examining board:
Name |
Role |
|---|---|
| ADONIAS RIBEIRO FRANCO JÚNIOR | Examinador Externo |
| ANDRÉ GUSTAVO DE SOUSA GALDINO | Examinador Externo |
| ANTONIO CESAR BOZZI | Coorientador |
| CARLOS AUGUSTO CARDOSO PASSOS | Examinador Interno |
| MARCOS TADEU D AZEREDO ORLANDO | Presidente |
Pages
Summary: Supermartensitic stainless steels are widely used in the oil and gas industry due to their high mechanical strength, good toughness, corrosion resistance, and weldability. However, operation in environments containing abrasive particles, such
as silica and hematite, may compromise their durability through surface wear. Low temperature plasma thermochemical treatments have emerged as an alternative to increase surface hardness without significantly impairing corrosion resistance,
promoting the formation of expanded martensite. In this work, the tribological behavior of Super 13Cr steel subjected to plasma nitriding and nitrocarburizing at 400 °C and 450 °C was investigated. The samples were characterized by optical and scanning electron microscopy, X-ray diffraction, glow discharge optical emission spectroscopy (GDOES), and microhardness testing, while wear resistance was evaluated by microabrasion using abrasives of different severities ((SiC, SiO2 and Fe2O3), complemented by scratch tests. The treatments promoted a significant increase in surface hardness and the formation of expanded martensite enriched with nitrogen and carbon. Microabrasion results indicated that the abrasive type was the main factor influencing wear, as confirmed by two-way ANOVA. Under severe conditions using SiC abrasive, no significant improvement in wear resistance was
observed due to the high hardness ratio between abrasive and material, resulting in severe scratching and removal of the modified layer. For less severe abrasives, such as silica and hematite, treatments at 450 °C reduced wear by approximately 50% and 40%, respectively, associated with increased layer thickness and load-bearing capacity. Scratch tests showed a reduction in the stylus drag coefficient in the treated samples, with the best performance observed at 450 °C. Nitrocarburizing at 400 °C
exhibited limitations under high loads due to the reduced coating thickness, whereas CN450 presented the best overall performance. The nitrided samples were dominated by micro-cutting due to their high hardness and lower plastic deformation
capacity, while the nitrocarburized samples showed lower fab values and greater pile-up formation, indicating microsulcating and higher plastic accommodation.
