Surgical steel

Cobalt ores are often found in association with copper(II) sulfide. Cobalt is a silver-gray metal and is used mainly for alloying with iron. Alnico steel, an alloy of iron, nickel, cobalt, and aluminum, is used to make permanent magnets such as those in loudspeakers. Cobalt steels are hard enough to be used as surgical steels, drill bits, and lathe tools. The color of cobalt glass is due to a blue pigment that forms when cobalt(II) oxide is heated with silica and alumina. 

Disa, J.J., Vossoughi, J. and Goldberg, N.H. (1993). A comparison of obsidian and surgical steel scalpel wound-healing in rats. Plastic and Reconstructive Surgery 92 884-887. 

Metal Surgical steels Osseosynthetic plates and Biotolerant/ Heness and Ben-Nissan... 

The polarisation resistance can be related to the rate of general corrosion for metals at or near their corrosion potential, corr. Polarisation resistance measurements are an accurate and rapid way to measure the general corrosion rate (CR) of bioinert Ti alloys, biotolerant austenitic surgical steels or biodegradable magnesium alloys. 

Figure 2.21 Orange oxides weeping from a tight seam in a martensitic (440) stainless steel surgical scissors. (Magnification 15x.)...

These quenched and tempered stainless steels are ideal for things like non-rusting ball-bearings, surgical scalpels and kitchen knives." ... 

Niobium finds use in the production of numerous stainless steels for use at high temperatures, and Nb/Zr wires are used in superconducting magnets. The extreme corrosion-resistance of tantalum at normal temperatures (due to the presence of an exceptionally tenacious film of oxide) leads to its application in the construction of chemical plant, especially where it can be used as a liner inside cheaper metals. Its complete inertness to body fluids makes it the ideal material for surgical use in bone repair and internal suturing. 

In the beginning of the twentieth century, surgical techniques were developed for the fixation of bone fractures with a plate and screw combination. Sherman-type bone plates were fabricated from the best available alloy at the time, vanadium steel. By the 1920s the use of vanadium steel became questionable because of poor tissue compatibility. At that time however, no other alloy was available with high strength and good corrosion resistant properties. 

Ogundele and White carried out a series of polarisation studies on surgical grade stainless steels in Hanks s physiological solution. Under... 

Pitting and stress corrosion cracking, although usually associated with stainless steels in chloride media, have not been observed on recovered surgical implants. Implants often exhibit cracks and surface pitting, but these are most likely the result of improper manufacture rather than corrosion . 

One of the most serious corrosion problems associated with type 316 stainless steel is its susceptibility to crevice corrosion. The incidence and extent of this type of corrosion in surgical implants was stressed by Scales eta/. who reported the presence of crevice corrosion in 24% of type 316L bone plates and screws examined after removal from patients. This record however compared favourably with the presence of crevice corrosion in 51 % of 18-8 stainless plates, demonstrating the superiority of the molybdenum-containing grade. 

Intercrystalline corrosion was a serious problem with the austenitic stainless steels early in their development since carbon contents then were relatively high, e.g. En58J contained up to 0.12type stainless steel contained up to 0.08 Vo C. The problem in relation to surgical implants has been reported by Scales eta/. and as a result of this and several other reports the British, American and International Standards specified the use of a 316S12 type austenitic stainless steel which contains 0.03 Vo C max. The use of the lower carbon content stainless steels as specified in the various standards has now eliminated the problem of sensitisation of implants. If manufacturers do use the 0.08% C versions they have to be very careful with the forging temperatures or anneal the prostheses afterwards. 

Ogundele, G. I. and White, W. E., Polarization Studies on Surgical-Grade Stainless Steels in Hanks Physiological Solution , in Corrosion and Degradation of Implant Materials, second symposium, (Eds) A. C. Fraker and C. D. Griffin, 117-135 ASTM Publication STP 859, Philadelphia (1985)... 

Tin is soft and it does not rust. It is used to coat steel in tin cans, watch parts, coffee pots, and surgical tools to protect the articles from rusting. 

Finally, alternatives exist to the use of silver in various materials and processes. These include substitution of aluminum and rhodium for silver in mirrors and other reflecting surfaces tantalum replacement of silver in surgical plates, pins, and sutures stainless steel as an alternative material to silver in the manufacture of table flatware and, in photography, film with reduced silver content (Reese 1991). 

Stainless steels Alloy 2C cast and wrought in galvanic series, 7 805t Stainless steel surgical needles, 24 206 Stain removal... 

Titanium alloys generally show a combination of strength and biocompatibility which makes them suitable for medical devices (prosthesis, surgical instruments). The high strength Ti-6Al-7Nb alloy has several orthodontic applications. Only a limited number of alloys have the necessary combinations of properties needed for successful use in the human body. Titanium and its alloys, stainless steels and cobalt-chromium alloys are the workhorse alloys in the medical device industry. 

For surgical parts, the replacement of stainless steel by liquid crystal polymer (TCP) leads to a material cost of the same order, but the ease of TCP processing compared to metal results in a lower final cost. The cost savings are about 50% for some standard parts and up to 90% for high-tech parts. 

About 90% of all the zirconium produced in the United States is used in the nuclear electrical power industry. Since it does not readily absorb neutrons, it is a desired metal in the manufacture of nuclear reactors and their fuel tubes, but it must be free of its twin hafnium for these purposes. Zirconium is also used as an alloy with steel to make surgical instruments. 

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