Titanium is a popular transitional metal that is used in the manufacturing of many products including jewelry, surgical tools, tennis racks, and much more. These characteristics along with superior corrosion-resistance make titanium a highly sought after component for the creation of a countless number of products.
This is your guide to understanding the differences between Alpha-Beta Titanium and Commercially Pure Titanium, as well as learning how the use of both versions of titanium can help increase your bottom line. When it comes to choosing the best titanium to fit your needs, there are a few different factors you must take into consideration. You first, have to make sure that the type chosen will fulfill the requirements to create a high-quality product.
In many cases, such as the aerospace and medical industries, lives depend on it. The second factor is choosing titanium that will meet your needs while also being cost-effective. In other words, you do not want to pay more than you need to for a product that overshoots your needs. On the other hand, you do not want to waste money on titanium that doesn't meet all of your needs either.
For many, Alpha-Beta titanium has all of the characteristics needed to ensure a quality product, while helping to keep production costs as low as possible. Alpha-Beta titanium is an alloy ti alloy , which is the combination of two or more metals. The outcome results in a product that is stronger than any of the parent elements.
Titanium alloys are known to have two primary phases. These are the alpha and beta phases. These phases are further broken down into subcategories including Alpha, near-Alpha, Beta, near-Beta, and of course the one we are most interested in today, Alpha-Beta. It is the differences in orientations of the molecules in these phases that give titanium alloys unique properties.
The Alpha-Beta phase is comprised of alpha and transformed beta molecules. It is important to note that Alpha-Beta titanium alloys co-exist and have the ability to be further processed to give an even more diverse set of properties that make this metal ideal for an array of applications across numerous industries. Alpha-Beta Titanium often contains alloying elements such as Aluminum or Vanadium and these lead to great corrosion resistance and use at high temperatures, making them great candidates for Aerospace applications.
Alpha-Beta phase titanium has many attractive properties that make it highly sought after in the manufacturing industry. These include:. This Alpha-Beta phase titanium was dubbed as the "workhorse" of titanium and for good reason.
It has excellent strength, compared to commercially pure titanium, but yet retains the stiffness and thermal properties that are so important. This alloy offers users the best of both worlds and gives it useful applications across several industries. It is most beneficial for industries that need a lightweight, heat-resistant, yet strong metal.
However, when choosing titanium alloys you should know about a less well-known Alpha-Beta phase titanium alloy known as Grade 9 or Ti It is much stronger than commercially pure titanium and easier to work with than Grade 5 due primarily to the fact that it can be worked cold. Other properties that lead to it being an easier alloy to work with is that Grade 9 provides good ductility, moderate strength, and superb resistance to corrosion. Both Alpha-Beta alloys are top-of-the-line, but if Grade 9 can accommodate your needs, it is much more cost-effective than Grade 5.
Alpha-Beta alloys possess certain titanium properties that allow them to work well for the manufacturing of products across a variety of industries. The most common industries include chemical processing, aerospace, medical, and marine. Specific products that Alpha-Beta titanium alloys are used in include but are not limited to:.
As you can see Alpha-Beta titanium alloys, especially Grade 9 is a great way to provide the utmost quality to clients while trimming costs as much as possible compared to commercially pure titanium.
There are 38 grades of titanium, with increases in grade numbers being inversely proportional to metal quality. Impurities can be removed from impure titanium, and other metals added to form the three groups of titanium alloys: Alpha, Beta and Alpha-Beta, where Alpha-Beta goes on to be the most used alloy. There are four commercially pure grades of Titanium, Grades Unalloyed titanium CP Ti runs from grade one to four and consists of between Grade five onwards fall into alloys of titanium.
Titanium circuit board hybrids promise a new era in the manufacture of circuit boards. They can do more than traditionally printed circuit boards, or PCBs, are hardy and work well in hostile environments.
A titanium electronic circuit board is made by the precision screen printing and firing of conductors, dielectrics and resistors onto the titanium metal.
Titanium hybrids have a much higher reliability due to fewer solder interconnections and also have extremely accurate active circuit calibration. They operate on a wider operating temperature range, are very compact — being half the size of the most complex PCBs — and are fully enclosed for complete protection from the environment. Titanium circuits can also be used in applications that involve heating elements, weighing, load cells and force measurement, and can be used for flow measurement, fluid pressure and temperature measurement and strain gauge applications.
Titanium is one of the most bio-compatible metals — the human body can handle it with no harmful effects. Its mechanical properties include improved resistance to wear and tear, high elasticity, and good hot and cold formability, which make it perfect for use in surgical implants like hip balls, joint replacements, heart stents and tooth implants.
Uncover the next big growth opportunity. Download our white paper for free to learn about emerging and future opportunities for titanium suppliers and an easy way to reach new buyers online. From surgical titanium instruments to orthopaedic titanium rods, plates and pins, medical and dental titanium have now become the material of choice. Titanium is also non-toxic and has the ability to withstand corrosion from bodily fluids.
Not only incredibly durable, titanium is long-lasting, and when titanium cages, rods, plates and pins are inserted into the body, they can last for twenty years or more. One possible alternative to solve tribological problems and which is going to explain more detail consists of protecting the alloy surface by means of biocompatible Diamond-Like Carbon DLC coatings.
DLC coatings basically consist of a mixture of diamond sp 3 and graphite sp 2. The relative amounts of these two phases will determine much of the coating properties. Both the mechanical and the tribological properties of DLC coatings have been studied for about 30 years, and several different types of DLC coatings can currently be found. DLC films are attractive biomedical materials due to their relatively high hardness, low friction coefficient, owing to the solid lubricant because of its graphite and amorphous carbon contents [ 31 ], good chemical stability and excellent bio and hemocompatibility [ 45 ] [ 44 ] [ 46 ] [ 47 ].
Cells are seen to grow well on these films coated on titanium and other materials without any cytotoxicity and inflammation. Oxidation remains the most popular technique for the surface modification of Ti alloys; these oxide layers on titanium are commonly produced by either heat treatment [ 48 ] [ 49 ] [ 50 ] or electrolytic anodizing [ 51 ].
Conventional anodic oxidation, which is carried out in various solutions providing passivation of the titanium surface, generates thin films of amorphous hydrated oxide or crystalline TiO 2 in the anatase form [ 52 ].
These films exhibit poor corrosion resistance in some reducing acids and halide solutions, while rutile generally possesses much better protective properties. By anodic oxidation, elements such as Ca and P can be imported into the surface oxide on titanium and the micro-topography can be varied through regulating electrolyte and electrochemical conditions. The presence of Ca-ions has been reported to be advantageous to cell growth, and in vivo data show implant surfaces containing both Ca and P enhance bone apposition on the implant surface.
Furthermore, there are alternative methods to improve the biocompatibility such as biocompatible chemicals [ 54 ] and materials such as ceramics for coating. Results indicated that pretreatment of the implant with phosphoric acid caused no citotoxicity to the osteoblasts [ 55 ]. Micro arc oxidation method in phosphoric acid on titanium implants provided chemical bonding sites for calcium ions during mineralization [ 56 ]. Moreover, there have been developed coatings for high osseointegration.
The higher the degree of osseointegration, the higher is the mechanical stability and the probability of implant loosening becomes smaller. The process of osseointegration depends upon the surface properties such as surface chemistry, surface topography, surface roughness and mainly the surface energy. This technique is based on the modification of the growing anodic film by arc micro-discharges, which are initiated at potentials above the breakdown voltage of the growing oxide film and move rapidly across the anode surface.
This technology provides a solution by transforming the surface into a dense layer of ceramic which not only prevents galling but also provides excellent dielectric insulation for contact metals, helping to protect them against aggressive galvanic corrosion.
PEO process transforms the surface of titanium alloys into a complex ceramic matrix by passing a pulsed, bi-polar electrical current in a specific wave formation through a bath of low concentration aqueous solution.
A plasma discharge is formed on the surface of the substrate, transforming it into a thin, protective layer of titanium oxide, without subjecting the substrate itself to damaging thermal exposure.
Among all the above mentioned surface treatments, Diamond-Like Carbon coating and Plasma Electrolytic Oxidation are the most promising ones applied on titanium surfaces. These two treatments are explained in more detail in the following sections. In some biomedical applications continuously sliding contact is required, subjecting the implant to aggressive situations. Classification of coatings with respect to hardness and coefficient of friction, highlighting the special case of carbon-based coatings.
It would thus seem to be difficult to associate low friction and high wear resistance with all types of coating in most tribological contacts. Some trade-offs can be found in combining both hard and soft materials in composite or multilayer coatings, which require complex procedures and further optimization of the deposition process.
In some cases, friction values lower than 0. These exceptional tribological abilities explain the increasing success of Diamond-Like Carbon coatings over the years, both in industrial applications and in the laboratory. The exceptional tribological behavior of Diamond-Like Carbon films appears to be due to a unique combination of surface chemical, physical, and mechanical interactions at their sliding interfaces [ 65 ]. Since their initial discovery in the early s, Diamond-Like Carbon coatings have attracted the most attention in recent years, mainly because they are cheap and easy to produce and offer exceptional properties for demanding engineering and medical applications.
They can be used in invasive and implantable medical devices. These films are currently being evaluated for their durability and performance characteristics in certain biomedical implants including hip and knee joints and coronary stents.
Diamond-Like Carbon is the only coating that can provide both high hardness and low friction under dry sliding conditions. These films are metastable forms of carbon combining both sp2 and sp3 hybridizations, including hydrogen when a hydrocarbon precursor is used during deposition. Scheme of titanium doped DLC coating. In this case, the first titanium layer was deposited in order to improve adhesion of DLC coating to the substrate and relax stress of the coating. It is well known that Diamond-Like Carbon films usually present smooth surfaces, except maybe in the case of films formed by unfiltered cathodic vacuum arc deposition Figure 7.
Roughness of the films on industrial surfaces will then be mainly controlled by the substrate roughness and can therefore be minimized. SEM Scanning electron microscopy micrograph of Ti-DLC coating deposited by physical vapour deposition technique using cathodic arc evaporation method.
A frequently observed feature in tribological testing of Diamond-Like Carbon films is the formation of transfer layer. The formation of carbonous transfer layer on the sliding surface was observed to reduce the friction coefficient [ 68 ]. An arc can be defined as a discharge of electricity between two electrodes. The arc evaporation process begins with the striking of a high current, low voltage arc on the surface of a cathode that gives rise to a small usually a few microns wide highly energetic emitting area known as a cathode spot.
The metal is evaporated by the arc in a single step, and ionized and accelerated within an electric field. Theoretically the arc is a self-sustaining discharge capable of sustaining large currents through electron emission from the cathode surface and the re-bombardment of the surface by positive ions under high vacuum conditions. If a reactive gas is introduced during the evaporation process dissociation, ionization and excitation can occur during interaction with the ion flux and a compound film will be deposited.
Without the influence of an applied magnetic field the cathode spot moves around randomly evaporating microscopic asperities and creating craters. However if the cathode spot stays at one of these evaporative points for too long it can eject a large amount of macro-particles or droplets as seen above. These droplets are detrimental to the performance of the coating as they are poorly adhered and can extend through the coating.
SEM micrographs of the fretting tests wear scars. Cellular behaviors, e. The natural oxide is thin about 3—10nm in thickness [ 39 ] amorphous and stoichiometrically defective. It is known that the protective and stable oxides on titanium surfaces are able to provide favorable osseointegration [ 73 ] [ 74 ]. The stability of the oxide depends strongly on the composition structure and thickness of the film [ 75 ].
On titanium and its alloys a thin oxide layer is formed naturally on the surface of titanium metal in exposure to air at room temperature [ 76 ] [ 77 ] [ 78 ].
Titania TiO 2 exists in three polymorphic forms: rutile, anatase and brookite. Rutile, stable form of titania at ambient condition, possesses unique properties [ 79 ]. The metastable anatase and brookite phases convert to rutile upon heating. However, contact loads damage this thin native oxide film and cause galvanic and crevice corrosion as well as corrosion embrittlement.
Moreover, the low wear resistance and high friction coefficient without applied protective coatings on the surface gravely limit its extensive applications. The most accepted technique for the surface modification of Ti alloys is oxidation. Anodizing produces anatase phase of titania that shows poor corrosion resistance in comparison with rutile phase. Attempts to improve surface properties of titanium and its alloys over the last few decades have led to development of Plasma Electrolytic Oxidation PEO technique by Kurze et al.
At the same time the local temperature and pressure inside the discharge channel can reach 10 -3 -4 K and 10 -2 -3 MPa, respectively, which is high enough to give rise to plasma thermo-chemical interactions between the substrate and the electrolyte. These interactions result in the formation of melt-quenched high-temperature oxides and complex compounds on the surface, composed of oxides of both the substrate material and electrolyte-borne modifying elements.
The result is a porous oxide coating. Photography of the arc micro-discharges in PEO process. The coating becomes increasingly compact on going towards the interface with the substrate. This kind of morphology leads to a relatively high surface roughness. This method is characterized by the titanium surface, at near-to-ambient bulk temperature, into the high temperature titanium oxide rutile modified by other oxide constituents.
Economic efficiency, ecological friendliness, corrosion resistance, high hardness, good wear resistance, and excellent bonding strength with the substrate are the other characteristics of this treatment [ 82 ] [ 83 ] [ 84 ]. The main conversion products formed by the PEO treatment are titanium oxides: rutile and anatase, typical anodic oxidation products of titanium.
The structure and composition of anodic oxide films are known to be strongly dependent on film formation temperature and potential [ 85 ] [ 86 ]. In the case of PEO coatings, both the electrolyte composition and the current density regime have an influence on the phase composition and morphology of the anodic oxide layer [ 87 ].
A higher spark voltage causes a higher level of discharge energy, which provides a larger pore [ 88 ]. The influence of electrolyte characteristics on the phase composition of PEO films on titanium has previously been studied [ 89 ] [ 90 ]. Ca and P ions can be incorporated into the layer, controlling the electrolyte employed during the electro oxidation process, and they further transform it into hydroxyapatite by a hydrothermal treatment [ 41 ].
One technique that could show the effect of the electrolyte in the chemical composition of the coating could be the EDS Energy Dispersive Spectroscopy technique.
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