Surface cleanliness requirements depend on which nitrocarburizing process is selected for component treatment. This chapter discusses the processes involved in some of the more commonly used precleaning methods for gas ferritic nitrocarburizing and provides information on the methods used to accomplish enhanced plasma cleaning.

Cleaning procedures serve to remove scale, tarnish films, and other contaminants that form or are otherwise deposited on the surface of titanium during processing operations such as hot working and heat treatment. This chapter explains what makes titanium susceptible to the formation of scale and how it can be removed via belt grinding, abrasive blasting, and molten salt descaling baths. It also discusses the role of acid pickling, barrel finishing, polishing, and buffing as well as the use of chemical conversion coatings and protective platings.

Superalloys are susceptible to damage from a variety of surface contaminants. They may also require special surface finishes for subsequent processing steps such as coating applications. This chapter describes some of the cleaning and finishing procedures that have been developed for superalloys and how they work. It discusses the effect of metallic contaminants, tarnish, oxide, and scale and how they can be detected and removed. It also discusses chemical and mechanical surface finishing techniques and where they are used, and presents several application examples.

The surface condition of metals can have a significant effect on the outcome of high-temperature processes and vice versa. This chapter discusses the general cleaning and surface treatment needs of work in-process both before and after induction hardening. It identifies contaminants and defects associated with various quenchants and processing atmospheres and provides insights on how they can be removed and, in some cases, prevented. It also recommends the application of a rust preventative shortly after parts have cooled.

This chapter covers a wide range of finishing and coating operations, including cleaning, honing, polishing and buffing, and lapping. It discusses the use of rust-preventative compounds, conversion coatings, and plating metals as well as weld overlay, thermal spray, and ceramic coatings and various pack cementation and deposition processes. It also discusses the selection and use of industrial paints and paint application methods.

Cold spray coatings technology has the potential to provide surface enhancement for applications in sectors such as defense and aerospace, oil and gas, power generation, medical, automotive, electronics, and railways. The ability to deposit clean metallic coatings is used in applications requiring corrosion/oxidation protection, erosion/wear protection, additive manufacturing, and fabricating free forms. This chapter discusses the function, advantages, and benefits of some of these applications.

This chapter discusses corrosion prevention methods used with aluminum and its alloys. The methods range from relatively straightforward measures, such as proper handling and storage, to advanced early warning corrosion monitoring systems for military aircraft. The chapter summarizes the basic factors that influence design for corrosion resistance and discusses the use of conversion coatings, organic coatings, porcelain enameling, and electroplating. It also discusses corrosion monitoring methods used in chemical processing and refining industries.

This chapter discusses the functions of surface treatments important for stainless steel, namely the removal of oxide scale and cleaning, brightening, and coloring of the stainless surface. Details on the main methods of producing aesthetic surface finishes are also provided.

Ferritic nitrocarburizing accomplishes surface treatment of a part in the ferrite region of the iron-carbon equilibrium diagram. This chapter presents the history and process benefits of ferritic nitrocarburizing.

This chapter provides helpful guidelines for selecting a surface treatment for a given application. It identifies important design factors and applicable treatments for common design scenarios, materials, and operating conditions. It explains why heat treatments and finishing operations may be required before or after processing and how to estimate or predict coating thickness, case depth, hardness, and the likelihood of distortion. It also addresses related issues and considerations such as part handling and fixturing, surface preparation and cleaning requirements, processability, aesthetics, and the influence of design features.

This chapter discusses joining atmospheres that are used for brazing, along with their advantages and disadvantages. It discusses the processes, advantages, and disadvantages of chemical fluxing, self-fluxing, and fluxless brazing. Information on stop-off compounds that are considered as the antithesis of fluxes is also provided.

This chapter begins with an overview of the history of ion nitriding. This is followed by sections that describe how the ion nitriding process works, glow discharge characteristics, process parameters requiring good control, and the applications of plasma processing. The chapter explores what happens in the ion nitriding process and provides information on its gas ratios. It describes the reactions that occur at the surface of the material being treated during iron nitriding and defines corner effect and nitride networking. Further, the chapter provides information on the stability of surface layers and processes involved in the degradation of surface finish and control of the compound zone formation. Gases primarily used for ion nitriding and the control parameters used in ion nitriding are also covered. The chapter also presents the philosophies and advantages of the plasma generation technique for nitriding. It concludes with processes involved in oxynitriding.

This chapter discusses the practices and procedures used to reveal and record macrostructural features such as hardening depth, weld thickness, crack size, porosity, hot folds, and machining and tooling marks. It provides information on sectioning, sample location, orientation, surface grinding, and etching. It describes macrographic etchants and the features they reveal along with common etching problems and how to avoid them. It explains how to evaluate etching results and how they can be improved using remedial processes such as light grinding. It also discusses photographic reproduction, lighting, and image enhancement techniques.

Materials used in joining, whether solders, fluxes, or atmospheres, are becoming increasingly subjected to restrictions on the grounds of health, safety, and pollution concerns. These regulations can limit the choice of materials and processes that are deemed acceptable for industrial use. The chapter addresses this issue with a focus on soldering fluxes. The chapter also describes factors related to soldering under a protective atmosphere, provides information on chemical fluxes for soldering of various metals, and discusses the processes involved in fluxless soldering processes.

This chapter deals with the technology of stainless steel as it pertains to its proper use in architecture, art, and construction. It begins with an overview of the corrosion resistance of stainless steel, providing guidelines for balancing corrosion resistance, processing characteristics, and economy. This is followed by sections describing the influence of surface finish on corrosion resistance of stainless steel and reviewing some of the factors pertinent to balancing service environment, design requirements, and maintenance considerations. The chapter then discusses the various factors pertinent to important considerations in buildings, namely surface finish aesthetics, flatness, maintenance, repair, fabrication, and service considerations. It ends with a section providing information on concrete reinforcing bar.

Contaminants can be a cause of numerous types of system failures. There are numerous techniques for confirming contaminant presence. When the presence of a contaminant is suspected, the failure analysis team must find and eliminate the contaminant source, which can be obvious or quite subtle. This chapter summarizes a few commonly encountered contaminant sources to stimulate the reader's thinking about potential contaminant sources. A case study of titanium component washing at Litton Lasers is presented to illustrate how the presence of contaminants leads to a system failure.

Ion nitriding equipment can be categorized into two groups: cold-wall continuous direct current (dc) equipment and hot-wall pulsed dc equipment. This chapter focuses on these two categories along with other important considerations for ion (plasma) nitriding equipment and processing. Other important considerations discussed include the hollow cathode effect, sputter cleaning, furnace loading, pressure/voltage relationships, workpiece masking, and furnace configuration options. The chapter describes five methods of cooling parts from the process temperature to an acceptable exposure temperature after plasma nitriding. The chapter also presents some of the advantages of the pulsed plasma process.