Platinum is the first of the robotic Metal Men and the result of the scientific and technological genius of Doctor Will Magnus. Although there is no real gender among the Metal Men, she is the only one programed to act as a female. Unlike other robots, the Metal Men have a responsometer which allows them a certain degree of personality similar to that of a human.
The Metal Men consistently challenged the lines between human and robot relationships as Doctor Magnus’ creations were often depicted also as his best friends. As Platinum is supposed to represent a female character, this brought into stories a question about love between humans and robots. As such Tina is often represented as the most human of the Metal Men as it obvious by the fact that she was given a human name (Tina) though this itself is just a play on her own name. Although she was friends with all of the Metal Men, she often was antagonized by Mercury whose less-serious attitude aggravated her at times. Her feminine programming makes her appreciate some bizarre things such as Betty Boop cartoons, and outside of her infatuation with Doctor Magnus she also makes suggestive comments to others such as Batman.
Perhaps her most important story arc of all was her introduction when she convinced Doctor Magnus of the need to create a group of Metal Men to avert a potential world crisis. Thus Gold, Lead, Iron, Mercury and Tin were all eventually created. As she appeared in the late golden age/early silver age of comics, the majority of her stories (and those of her teammates) were told in self-contained issues with not as much continuity between them. For instance in the first appearance of the Metal Men in their own series, Platinum must deal with the King of the Missile Men who wants her as his queen. Throughout this period the same level of story continued, but if there was any constants among the team it was that Chemo was a frequent enemy. With the end of their series their adventures were not depicted as often anymore although they appeared in the occasional ongoing monthly as guest characters. The team took part in DC wide crossovers such as Crisis on Infinite Earths, Infinite Crisis and 52, though generally in a supporting role, and really this has been their state since the height of their popularity. As one of the more recognizable members of the Metal Men she is more often seen in cameos (such as in one of the reboots of the Justice League of America.) More recently she has received a redesign and a new name (Platina) though this is not considered canonical.
The New 52
Re-introduced in Justice League, Platinum was invited to the Watchtower by Cyborg at the recommendation of his father. She was invited as a favor to Will Magnus. She is introducing herself to the others in the Watchtower and she is sent in by the U.S. government to operate in dangerous and toxic environments that are harmful to humans. During the meeting of heroes, Platinum went out of control and began attacking some of the new recruits. She repeatedly asks where Will Magnus is during the battle. Once Cyborg learned of her weak point via Dr. Magnus, Firestorm converted Platinum's body into water while the responsometer was caught by the new Atom, Rhonda Pineda, ultimately taking Platinum offline.
Powers and Abilities
She can stretch her body into different shapes as well as shape shift. Her metallic body means that she has greater durability to damage and has increased strength as well as certain physiological necessities for humans (to breathe air) are not necessary. Each of the Metal Men take their name specifically from the metal they are made from and in which case they also retain the properties of those elements. In Platinum's case this means that she can use herself to be highly conductive of heat or electricity. Conversely this is also a weakness of her as the characteristics of platinum can be used against her. At one point Doctor Magnus used a solution of Aqua Regia to attack her when she was being controlled by others, as this substance dissolves platinum.
Batman: The Brave and the Bold
The Metal Men have appeared three times in this show. The first episode they appeared in was "Clash of the Metal Men" where they assist Batman in rescuing Dr. Milton Magnus from the Gas Gang. The next appearance was in the opening segment of "The Super-Batman of Planet X!" where their are disguised as various things on Dr. Magnus to help Batman take down Kanjar Ro and his gang of intergalactic space bandits. Platinum was seen inside Lead when he was a briefcase. Their final appearance in the show was "The Siege of Starro! Part Two" where they assisted Batman and the Justice League in fighting Starro.
Justice League: The New Frontier
She and other Metal Men appear at the end of the movie in a cameo along with other Heroes and Teams.